Professor Stephen Sweeney

Professor of Physics, EPSRC Leadership Fellow, Head of Photonics group

Qualifications: BSc (Bath) CertEd (Bath) PhD (Surrey) QTS CPhys MInstP SenMIEEE

Email:
Phone: Work: 01483 68 9406
Room no: 12 ATI 01

Office hours

12ATI01 (Email for appointments)

Further information

Research Interests

Stephen's primary research interests lie in the area of semiconductor laser physics with a particular onus on optimising laser performance. He has produced >150 journal papers and conference proceedings in this area including several invited papers. Stephen has recently expanded his interests into photonic sensors based on both III-V and Si technologies. Recent topics include:

  • semiconductor lasers for temperature insensitive operation (quantum dots, dilute-nitrides etc)
  • widely tunable lasers
  • vertical cavity surface emitting lasers and LEDs for plastic fibre systems
  • semiconductor lasers for optical pumping (EDFA, Raman) and printing and data storage applications
  • using photonic devices to sense chemical and biological samples (liquids and gases)

Information about currently available PhD projects can be found here

Research Collaborations

Current and previous collaborators include:
Commercial:

  • JDS
  • Bookham
  • Infineon
  • Fujitsu
  • Agilent
  • CIP
  • Philips
  • Cedova
  • LSA


Academic:

  • Arizona State University
  • Philips Universitaet Marburg
  • Universitaet Wuerzburg
  • Okayama University
  • Stanford University
  • Tampere University of Technology
  • Imperial College London
  • Sheffield University
  • Tyndall Institute, Cork
  • UC San Diego

Publications

Highlights

  • Usman M, Broderick CA, Batool Z, Hild K, Hosea TJC, Sweeney SJ, O'Reilly EP. (2013) 'Impact of alloy disorder on the band structure of compressively strained GaBixAs1-x'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 87 (11) Article number ARTN 115104
  • Sweeney SJ, Jin SR. (2013) 'Bismide-nitride alloys: Promising for efficient light emitting devices in the near- and mid-infrared'. Journal of Applied Physics, 113 (4)
  • Marko IP, Batool Z, Hild K, Jin SR, Hossain N, Hosea TJC, Sweeney SJ, Petropoulos JP, Zhong Y, Dongmo PB, Zide JMO. (2012) 'Temperature and Bi-concentration dependence of the bandgap and spin-orbit splitting in InGaBiAs/InP semiconductors for mid-infrared applications'. Applied Physics Letters, 101 (22)

    Abstract

    Replacing small amounts of As with Bi in InGaBiAs/InP induces large decreases and increases in the bandgap, E, and spin-orbit splitting, Δ, respectively. The possibility of achieving Δ > E and a reduced temperature (T) dependence for E are significant for suppressing recombination losses and improving performance in mid-infrared photonic devices. We measure E (x, T) and Δ (x, T) in InGa BiAs/InP samples for 0 x 0.039 by various complementary optical spectroscopic techniques. While we find no clear evidence of a decreased dE/dT (≈0.34 ± 0.06 meV/K in all samples) we find Δ > E for x > 3.3-4.3. The predictions of a valence band anti-crossing model agree well with the measurements. © 2012 American Institute of Physics.

  • Hossain N, Jin SR, Liebich S, Zimprich M, Volz K, Kunert B, Stolz W, Sweeney SJ. (2012) 'Efficiency-limiting processes in Ga(NAsP)/GaP quantum well lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 101 (1) Article number ARTN 011107
  • Batool Z, Hild K, Hosea TJC, Lu X, Tiedje T, Sweeney SJ. (2012) 'The electronic band structure of GaBiAs/GaAs layers: Influence of strain and band anti-crossing'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 111 (11) Article number ARTN 113108
  • Lever L, Hu Y, Myronov M, Liu X, Owens N, Gardes FY, Marko IP, Sweeney SJ, Ikonic Z, Leadley DR, Reed GT, Kelsall RW. (2011) 'Modulation of the absorption coefficient at 1.3 mu m in Ge/SiGe multiple quantum well heterostructures on silicon'. OPTICS LETTERS, 36 (21), pp. 4158-4160.

    Abstract

    We report modulation of the absorption coefficient at 1.3 μm in Ge/SiGe multiple quantum well heterostructures on silicon via the quantum-confined Stark effect. Strain engineering was exploited to increase the direct optical bandgap in the Ge quantum wells. We grew 9 nm-thick Ge quantum wells on a relaxed Si0.22Ge0.78 buffer and a contrast in the absorption coefficient of a factor of greater than 3.2 was achieved in the spectral range 1290–1315 nm.

  • Liebich S, Zimprich M, Beyer A, Lange C, Franzbach DJ, Chatterjee S, Hossain N, Sweeney SJ, Volz K, Kunert B, Stolz W. (2011) 'Laser operation of Ga(NAsP) lattice-matched to (001) silicon substrate'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (7) Article number ARTN 071109
  • Hild K, Marko IP, Johnson SR, Yu S-Q, Zhang Y-H, Sweeney SJ. (2011) 'Influence of de-tuning and non-radiative recombination on the temperature dependence of 1.3 mu m GaAsSb/GaAs vertical cavity surface emitting lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (7) Article number ARTN 071110
  • Ikyo BA, Marko IP, Adams AR, Sweeney SJ, Canedy CL, Vurgaftman I, Kim CS, Kim M, Bewley WW, Meyer JR. (2011) 'Temperature dependence of 4.1 mu m mid-infrared type II "W" interband cascade lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (2) Article number ARTN 021102
  • Mohmad AR, Bastiman F, Ng JS, Sweeney SJ, David JPR. (2011) 'Photoluminescence investigation of high quality GaAs1-xBix on GaAs'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 98 (12) Article number ARTN 122107
  • Sayid SA, Marko IP, Sweeney SJ, Barrios P, Poole PJ. (2010) 'Efficiency limiting processes in 1.55 mu m InAs/InP-based quantum dots lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 97 (16) Article number ARTN 161104

Journal articles

  • Chai GMT, Hosea TJC, Fox NE, Hild K, Ikyo AB, Marko IP, Sweeney SJ, Bachmann A, Arafin S, Amann M-C. (2014) 'Characterization of 2.3 mu m GaInAsSb-based vertical-cavity surface-emitting laser structures using photo-modulated reflectance'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 115 (1) Article number UNSP 013102
  • Jin S, John Sweeney S. (2013) 'InGaAsBi alloys on InP for efficient near- and mid-infrared light emitting devices'. Journal of Applied Physics, 114 (21)
  • Crutchley BG, Marko IP, Sweeney SJ. (2013) 'The influence of temperature on the recombination processes in blue and green InGaN LEDs'. Physica Status Solidi (C) Current Topics in Solid State Physics, 10 (11), pp. 1533-1536.
  • Tan SL, Soong WM, Green JE, Steer MJ, Zhang S, Tan LJJ, Ng JS, David JPR, Marko IP, Sweeney SJ, Adams AR, Allam J. (2013) 'Experimental evaluation of impact ionization in dilute nitride GaInNAs diodes'. Applied Physics Letters, 103 (10)

    Abstract

    The anomalous behavior of impact ionization in dilute-nitride GaInNAs photodiodes with a range of nitrogen content below 4% is investigated. The ratio of hole- and electron-initiated ionization coefficients, k = β/α, is enhanced by a factor up to ∼4 with increasing nitrogen content. The absolute ionization coefficients are suppressed by up to two orders of magnitude at low electric fields in samples with 3% N. The narrow band gap, suppressed impact ionization, and increased breakdown voltage characteristics of GaInNAs make it a suitable material for use as part of a composite collector in GaAs-based heterojunction bipolar transistors. © 2013 AIP Publishing LLC.

  • Pal J, Migliorato MA, Li C-K, Wu Y-R, Crutchley BG, Marko IP, Sweeney SJ. (2013) 'Enhancement of efficiency of InGaN-based light emitting diodes through strain and piezoelectric field management'. Journal of Applied Physics, 114 (7)
  • Mukherjee J, Jarvis S, Sweeney SJ, Perren M. (2013) 'Efficiency limits of laser power converters for optical power transfer applications'. Journal of Physics D: Applied Physics, 46 (26)
  • Ludewig P, Knaub N, Reinhard S, Nattermann L, Chatterjee S, Stolz W, Volz K, Hossain N, Marko IP, Jin SR, Hild K, Sweeney SJ. (2013) 'Electrical injection Ga(AsBi)/(AlGa)As single quantum well laser'. Applied Physics Letters, 102 (24)

    Abstract

    The Ga(AsBi) material system opens opportunities in the field of high efficiency infrared laser diodes. We report on the growth, structural investigations, and lasing properties of dilute bismide Ga(AsBi)/(AlGa)As single quantum well lasers with 2.2% Bi grown by metal organic vapor phase epitaxy on GaAs (001) substrates. Electrically injected laser operation at room temperature is achieved with a threshold current density of 1.56 kA/cm at an emission wavelength of ∼947 nm. These results from broad area devices show great promise for developing efficient IR laser diodes based on this emerging materials system. © 2013 AIP Publishing LLC.

  • Aldukhayel A, Jin SR, Marko IP, Sweeney SJ, Zhang SY, Revin DG, Cockburn JW. (2013) 'Investigations of carrier scattering into L-valley in λ=3.5μm InGaAs/AlAs(Sb) quantum cascade lasers using high hydrostatic pressure'. Physica Status Solidi (B) Basic Research, 250 (4), pp. 693-697.
  • Crutchley BG, Marko IP, Sweeney SJ, Pal J, Migliorato MA. (2013) 'Optical properties of InGaN-based LEDs investigated using high hydrostatic pressure dependent techniques'. Physica Status Solidi (B) Basic Research, 250 (4), pp. 698-702.
  • Usman M, Broderick CA, Batool Z, Hild K, Hosea TJC, Sweeney SJ, O'Reilly EP. (2013) 'Impact of alloy disorder on the band structure of compressively strained GaBixAs1-x'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 87 (11) Article number ARTN 115104
  • Sweeney SJ, Jin SR. (2013) 'Bismide-nitride alloys: Promising for efficient light emitting devices in the near- and mid-infrared'. Journal of Applied Physics, 113 (4)
  • Hossain N, Hild K, Jin SR, Sweeney SJ, Yu S-Q, Johnson SR, Ding D, Zhang Y-H. (2013) 'The influence of growth conditions on carrier recombination mechanisms in 1.3 μm GaAsSb/GaAs quantum well lasers'. Applied Physics Letters, 102 (4)

    Abstract

    We investigate the temperature and pressure dependence of the threshold current density of edge-emitting GaAsSb/GaAs quantum well (QW) lasers with different device characteristics. Thermally activated carrier leakage via defects is found to be very sensitive to the growth conditions of GaAsSb QWs. An optimization of the growth conditions reduces the nonradiative recombination mechanisms from 93% to 76% at room temperature. This improvement in carrier recombination mechanisms leads to a large improvement in the threshold current density from 533 Acm/QW to 138 Acm/QW and the characteristic temperature, T (T), from 51 ± 5 K (104 ± 16 K) to 62 ± 2 K (138 ± 7 K) near room temperature. © 2013 American Institute of Physics.

  • Batool Z, Hild K, Hosea TJC, Jin S, Sweeney SJ, Chatterjee S, Chernikov A, Fritz R, Koch M, Koch SW, Kolata K, Volz K, Duzik A, Millunchick JM, Thomas JC, Gogineni C, Johnson SR, Lu X, Riordan NA, Imhof S, Thränhardt A, Jiang Z, Mooney PM, Lewis RB, Masnadi-Shirazi M, Tiedje T, Rubel O. (2013) 'Bismuth-containing III-V semiconductors: Epitaxial growth and physical properties'. Molecular Beam Epitaxy, , pp. 139-158.
  • Lester LF, Kovanis V, Sze-Chun Chan N, Miyamoto T, Sweeney SJ. (2013) 'Introduction to the issue on semiconductor lasers'. IEEE Journal on Selected Topics in Quantum Electronics, 19 (4)
  • Maspero R, Sweeney SJ, Florescu M. (2013) 'Modelling the Auger Recombination rates of GaAsBi alloys'. 13th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2013, , pp. 81-82.
  • Ongrai O, Pearce JV, Machin G, Sweeney SJ. (2013) 'Self-calibration of a W/Re thermocouple using a miniature Ru-C (1954 °c) eutectic cell'. AIP Conference Proceedings, 1552 8, pp. 504-509.
  • Lock DA, Prins AD, Crutchley BG, Kynaston S, Sweeney SJ, Hall SRG. (2013) 'LED junction temperature measurement using generated photocurrent'. IEEE/OSA Journal of Display Technology, 9 (5), pp. 396-401.
  • Srinivasan S, Tang Y, Read G, Hossain N, Hang D, Sweeney SJ, Bowers JE. (2013) 'HYBRID SILICON DEVICES FOR ENERGY-EFFICIENT OPTICAL TRANSMITTERS'. IEEE COMPUTER SOC IEEE MICRO, 33 (1), pp. 22-31.
  • Crutchley BG, Marko IP, Sweeney SJ. (2013) 'The influence of temperature on the recombination processes in blue and green InGaN LEDs'. Physica Status Solidi (C) Current Topics in Solid State Physics, 2 (12)
  • Tan SL, Hunter CJ, Zhang S, Tan LJJ, Goh YL, Ng JS, David JPR, Marko IP, Sweeney SJ, Adams AR, Allam J. (2012) 'Improved optoelectronic properties of rapid thermally annealed dilute nitride GaInNAs photodetectors'. Journal of Electronic Materials, 41 (12), pp. 3393-3401.

    Abstract

    We investigate the optical and electrical characteristics of GaInNAs/GaAs long-wavelength photodiodes grown under varying conditions by molecular beam epitaxy and subjected to postgrowth rapid thermal annealing (RTA) at a series of temperatures. It is found that the device performance of the nonoptimally grown GaInNAs p-i-n structures, with nominal compositions of 10% In and 3.8% N, can be improved significantly by the RTA treatment to match that of optimally grown structures. The optimally annealed devices exhibit overall improvement in optical and electrical characteristics, including increased photoluminescence brightness, reduced density of deep-level traps, reduced series resistance resulting from the GaAs/GaInNAs heterointerface, lower dark current, and significantly lower background doping density, all of which can be attributed to the reduced structural disorder in the GaInNAs alloy.© 2012 TMS.

  • Marko IP, Batool Z, Hild K, Jin SR, Hossain N, Hosea TJC, Sweeney SJ, Petropoulos JP, Zhong Y, Dongmo PB, Zide JMO. (2012) 'Temperature and Bi-concentration dependence of the bandgap and spin-orbit splitting in InGaBiAs/InP semiconductors for mid-infrared applications'. Applied Physics Letters, 101 (22)

    Abstract

    Replacing small amounts of As with Bi in InGaBiAs/InP induces large decreases and increases in the bandgap, E, and spin-orbit splitting, Δ, respectively. The possibility of achieving Δ > E and a reduced temperature (T) dependence for E are significant for suppressing recombination losses and improving performance in mid-infrared photonic devices. We measure E (x, T) and Δ (x, T) in InGa BiAs/InP samples for 0 x 0.039 by various complementary optical spectroscopic techniques. While we find no clear evidence of a decreased dE/dT (≈0.34 ± 0.06 meV/K in all samples) we find Δ > E for x > 3.3-4.3. The predictions of a valence band anti-crossing model agree well with the measurements. © 2012 American Institute of Physics.

  • Broderick CA, Usman M, O'Reilly EP, Broderick CA, O'Reilly EP, Sweeney SJ. (2012) 'Band engineering in dilute nitride and bismide semiconductor lasers'. Semiconductor Science and Technology, 27 (9)
  • Blume G, Hild K, Marko IP, Hosea TJC, Sweeney SJ, Yu S-Q, Chaparro SA, Samal N, Johnson SR, Zhang Y-H. (2012) 'Cavity mode gain alignment in GaAsSb-based near-infrared vertical cavity lasers studied by spectroscopy and device measurements'. Journal of Applied Physics, 112 (3)

    Abstract

    We present a combination of spectroscopy and device measurements on GaAsSb/GaAs vertical-cavity surface-emitting laser (VCSEL) structures to determine the temperature at which the wavelength of the VCSEL cavity mode (CM) aligns with that of the quantum well (QW) ground-state transition (GST), and therefore the gain peak. We find that, despite the achievement of room temperature (RT) continuous wave lasing in VCSEL devices, the QW transition and the CM are actually slightly misaligned at this temperature; room temperature electroluminescence measurements from a cleaved edge of the VCSEL wafer indicate that the 300 K QW GST energy is at 0.975 ± 0.005 eV, while the CM measured in the VCSEL surface reflectivity spectra is at 0.9805 ± 0.0002 eV. When the wafer sample is cooled, the CM and QW GST can be brought into alignment at 270 ± 10 K, as confirmed by temperature-dependent electro-modulated reflectance (ER) and edge-electroluminescence spectroscopic studies. This alignment temperature is further confirmed by comparing the temperature dependence of the emission energy of a fabricated VCSEL device with that of an edge-emitting laser structure with a nominally identical active region. The study suggests that for further device improvement, the room temperature CM and QW GST energies should be more closely matched and both designed to a smaller energy of about 0.95 eV, somewhat closer to the 1.31 μm target. The study amply demonstrates the usefulness of non-destructive ER characterisation techniques in VCSEL manufacturing with GaAsSb-based QWs. © 2012 American Institute of Physics.

  • Mohmad AR, Bastiman F, Hunter CJ, Richards R, Sweeney SJ, Ng JS, David JPR. (2012) 'Effects of rapid thermal annealing on GaAs1-xBix alloys'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 101 (1) Article number ARTN 012106
  • Hossain N, Jin SR, Liebich S, Zimprich M, Volz K, Kunert B, Stolz W, Sweeney SJ. (2012) 'Efficiency-limiting processes in Ga(NAsP)/GaP quantum well lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 101 (1) Article number ARTN 011107
  • Batool Z, Hild K, Hosea TJC, Lu X, Tiedje T, Sweeney SJ. (2012) 'The electronic band structure of GaBiAs/GaAs layers: Influence of strain and band anti-crossing'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 111 (11) Article number ARTN 113108
  • Hossain N, Marko IP, Jin SR, Hild K, Sweeney SJ, Lewis RB, Beaton DA, Tiedje T. (2012) 'Recombination mechanisms and band alignment of GaAs1-xBix/GaAs light emitting diodes'. APPLIED PHYSICS LETTERS, 100 (5) Article number ARTN 051105
  • Buaprathoom S, Prins AD, Sweeney SJ, Pedley S. (2012) 'High concentration measurement of mixed particle suspensions using simple multi-angle light scattering system'. Proceedings of SPIE - The International Society for Optical Engineering, 8439

    Abstract

    A simple multiple-angle light scattering system was developed for the differential measurement of particle concentrations in suspension even in high concentration where multiple scattering effects are significant based on size. The system combines multiple-angle detection to collect scattered angle dependent light intensities, and Partial Least Square Regression method (PLS-R) to compose the predictive models for analyzing scattered signal obtain concentrations of samples under investigation. The system was designed to be simple, portable and inexpensive. It employs a diode lasers (red AlGaInP-based) as a light source and a silicon photodiode as a detector and optical components, all of which are readily available. The technique was validated using 1.1 μm and 3.0μm polystyrene latex beads in both mono-dispersed and poly-dispersed suspensions. The measurement results showed good agreement between the measured results and reference values. Their deviations from the reference values are 2.4% and 1.5% relating to references' concentrations of 1.3×10 and 1.2×10 particles/ml for 1.1 μm and 3.0 μm in mono-dispersed solutions and 2.3 % and 3.5% relating to references' concentrations of 1.1×10 and 4.4×10 particles/ml for 1.1 μm and 3.0 μm in mixed solutions, respectively. This system is a compact but high performance system allowing multiple particle sizes in high concentration to be measured simultaneously. © 2012 SPIE.

  • Tan SL, Hunter CJ, Zhang S, Tan LJJ, Goh YL, Ng JS, David JPR, Marko IP, Sweeney SJ, Adams AR, Allam J. (2012) 'Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors'. Journal of Electronic Materials, , pp. 1-9.
  • Reed GT, Thomson DJ, Gardes FY, Hu Y, Owens N, Yang X, Petropoulos P, Debnath K, O'Faolain L, Krauss TF, Lever L, Ikonic Z, Kelsall RW, Myronov M, Leadley DR, Marko IP, Sweeney SJ, Cox DC, Brimont A, Sanchis P, Duan G-H, Le Liepvre A, Jany C, Lamponi M, Make D, Lelarge F, Fedeli JM, Messaoudene S, Keyvaninia S, Roelkens G, Van Thourhout D, Liu S. (2012) 'High performance silicon optical modulators'. Proceedings of SPIE - The International Society for Optical Engineering, 8564

    Abstract

    In this work we present results from high performance silicon optical modulators produced within the two largest silicon photonics projects in Europe; UK Silicon Photonics (UKSP) and HELIOS. Two conventional MZI based optical modulators featuring novel self-aligned fabrication processes are presented. The first is based in 400nm overlayer SOI and demonstrates 40Gbit/s modulation with the same extinction ratio for both TE and TM polarisations, which relaxes coupling requirements to the device. The second design is based in 220nm SOI and demonstrates 40Gbits/s modulation with a 10dB extinction ratio as well modulation at 50Gbit/s for the first time. A ring resonator based optical modulator, featuring FIB error correction is presented. 40Gbit/s, 32fJ/bit operation is also shown from this device which has a 6um radius. Further to this slow light enhancement of the modulation effect is demonstrated through the use of both convention photonic crystal structures and corrugated waveguides. Fabricated conventional photonic crystal modulators have shown an enhancement factor of 8 over the fast light case. The corrugated waveguide device shows modulation efficiency down to 0.45V.cm compared to 2.2V.cm in the fast light case. 40Gbit/s modulation is demonstrated with a 3dB modulation depth from this device. Novel photonic crystal based cavity modulators are also demonstrated which offer the potential for low fibre to fibre loss. In this case preliminary modulation results at 1Gbit/s are demonstrated. Ge/SiGe Stark effect devices operating at 1300nm are presented. Finally an integrated transmitter featuring a III-V source and MZI modulator operating at 10Gbit/s is presented. © 2012 SPIE.

  • Mohmad AR, Bastiman F, Ng JS, Sweeney SJ, David JPR. (2012) 'Room temperature photoluminescence intensity enhancement in GaAs 1-xBi x alloys'. Physica Status Solidi (C) Current Topics in Solid State Physics, 9 (2), pp. 259-261.
  • Bastiman F, Mohmad ARB, Ng JS, David JPR, Sweeney SJ. (2012) 'Non-stoichiometric GaAsBi/GaAs (100) molecular beam epitaxy growth'. Elsevier Journal of Crystal Growth, 338 (1), pp. 57-61.
  • Sweeney SJ. (2012) 'Bismide alloys for photonic devices: Potential and progress'. 2012 IEEE Photonics Conference, IPC 2012, , pp. 602-603.
  • Bastiman F, Cullis AG, David JPR, Sweeney SJ. (2012) 'Bi incorporation in GaAs(100)-2×1 and 4×3 reconstructions investigated by RHEED and STM'. Elsevier Journal of Crystal Growth, 341 (1), pp. 19-23.
  • Buaprathoom S, Sweeney SJ, Pedley S. (2012) 'Dual wavelength multiple-angle light scattering system for cryptosporidium detection'. Society of Photo-Optical Instrumentation Engineers Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 8427

    Abstract

    A simple, dual wavelength, multiple-angle, light scattering system has been developed for detecting cryptosporidium suspended in water. Cryptosporidium is a coccidial protozoan parasite causing cryptosporidiosis; a diarrheal disease of varying severity. The parasite is transmitted by ingestion of contaminated water, particularly drinking-water, but also accidental ingestion of bathing-water, including swimming pools. It is therefore important to be able to detect these parasites quickly, so that remedial action can be taken to reduce the risk of infection. The proposed system combines multiple-angle scattering detection of a single and two wavelengths, to collect relative wavelength angle-resolved scattering phase functions from tested suspension, and multivariate data analysis techniques to obtain characterizing information of samples under investigation. The system was designed to be simple, portable and inexpensive. It employs two diode lasers (violet InGaN-based and red AlGaInP-based) as light sources and silicon photodiodes as detectors and optical components, all of which are readily available. The measured scattering patterns using the dual wavelength system showed that the relative wavelength angle-resolved scattering pattern of cryptosporidium oocysts was significantly different from other particles (e.g. polystyrene latex sphere, E.coli). The single wavelength set up was applied for cryptosporidium oocysts'size and relative refractive index measurement and differential measurement of the concentration of cryptosporidium oocysts suspended in water and mixed polystyrene latex sphere suspension. The measurement results showed good agreement with the control reference values. These results indicate that the proposed method could potentially be applied to online detection in a water quality control system. © 2012 SPIE.

  • Hunter CJ, Bastiman F, Mohmad AR, Richards R, Ng JS, David JPR, Sweeney SJ. (2012) 'Absorption characteristics of GaAsBi/GaAs diodes in the near-infrared'. IEEE Photonics Technology Letters, 24 (23), pp. 2191-2194.
  • Lever L, Hu Y, Myronov M, Liu X, Owens N, Gardes FY, Marko IP, Sweeney SJ, Ikonic Z, Leadley DR, Reed GT, Kelsall RW. (2011) 'Modulation of the absorption coefficient at 1.3 mu m in Ge/SiGe multiple quantum well heterostructures on silicon'. OPTICS LETTERS, 36 (21), pp. 4158-4160.

    Abstract

    We report modulation of the absorption coefficient at 1.3 μm in Ge/SiGe multiple quantum well heterostructures on silicon via the quantum-confined Stark effect. Strain engineering was exploited to increase the direct optical bandgap in the Ge quantum wells. We grew 9 nm-thick Ge quantum wells on a relaxed Si0.22Ge0.78 buffer and a contrast in the absorption coefficient of a factor of greater than 3.2 was achieved in the spectral range 1290–1315 nm.

  • Cheetham KJ, Krier A, Marko IP, Aldukhayel A, Sweeney SJ. (2011) 'Direct evidence for suppression of Auger recombination in GaInAsSbP/InAs mid-infrared light-emitting diodes'. APPLIED PHYSICS LETTERS, 99 (14) Article number ARTN 141110
  • Hild K, Marko IP, Johnson SR, Yu S-Q, Zhang Y-H, Sweeney SJ. (2011) 'Influence of de-tuning and non-radiative recombination on the temperature dependence of 1.3 mu m GaAsSb/GaAs vertical cavity surface emitting lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (7) Article number ARTN 071110
  • Liebich S, Zimprich M, Beyer A, Lange C, Franzbach DJ, Chatterjee S, Hossain N, Sweeney SJ, Volz K, Kunert B, Stolz W. (2011) 'Laser operation of Ga(NAsP) lattice-matched to (001) silicon substrate'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (7) Article number ARTN 071109
  • Hossain N, Sweeney SJ, Rogowsky S, Ostendorf R, Wagner J, Liebich S, Zimprich M, Volz K, Kunert B, Stolz W. (2011) 'Reduced threshold current dilute nitride Ga(NAsP)/GaP quantum well lasers grown by MOVPE'. INST ENGINEERING TECHNOLOGY-IET ELECTRONICS LETTERS, 47 (16), pp. 931-933.
  • Mohmad AR, Bastiman F, Hunter CJ, Ng JS, Sweeney SJ, David JPR. (2011) 'The effect of Bi composition to the optical quality of GaAs1-xBix'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (4) Article number ARTN 042107
  • Ikyo BA, Marko IP, Adams AR, Sweeney SJ, Canedy CL, Vurgaftman I, Kim CS, Kim M, Bewley WW, Meyer JR. (2011) 'Temperature dependence of 4.1 mu m mid-infrared type II "W" interband cascade lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 99 (2) Article number ARTN 021102
  • Tan SL, Zhang S, Soong WM, Goh YL, Tan LJJ, Ng JS, David JPR, Marko IP, Adams AR, Sweeney SJ, Allam J. (2011) 'GaInNAsSb/GaAs Photodiodes for Long-Wavelength Applications'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE ELECTRON DEVICE LETTERS, 32 (7), pp. 919-921.
  • Sweeney S. (2011) 'Selected papers from the Semiconductor and Integrated Optoelectronics (SIOE'10) Conference'. INST ENGINEERING TECHNOLOGY-IET IET OPTOELECTRONICS, 5 (3), pp. 99-99.
  • Mohmad AR, Bastiman F, Ng JS, Sweeney SJ, David JPR. (2011) 'Photoluminescence investigation of high quality GaAs1-xBix on GaAs'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 98 (12) Article number ARTN 122107
  • Hossain N, Hosea TJC, Sweeney SJ, Liebich S, Zimprich M, Volz K, Kunert B, Stolz W. (2011) 'Band structure properties of novel BxGa1-xP alloys for silicon integration'. JOURNAL OF APPLIED PHYSICS, 110 (6) Article number ARTN 063101
  • Kunert B, Liebich S, Zimprich M, Beyer A, Ziegler S, Volz K, Stolz W, Hossain N, Jin SR, Sweeney SJ. (2011) 'Electrical pumped integrated III/V laser lattice-matched to a Silicon substrate'. Device Research Conference - Conference Digest, DRC, , pp. 257-258.
  • Ongrai O, Pearce JV, Machin G, Sweeney SJ. (2011) 'A miniature high-temperature fixed point for self-validation of type C thermocouples'. MEASUREMENT SCIENCE & TECHNOLOGY, 22 (10) Article number ARTN 105103
  • Ongrai O, Pearce JV, Machin G, Sweeney SJ. (2011) 'Miniature Co-C eutectic fixed-point cells for self-validating thermocouples'. IOP PUBLISHING LTD MEASUREMENT SCIENCE & TECHNOLOGY, 22 (1) Article number ARTN 015104
  • Sayid SA, Marko IP, Sweeney SJ, Barrios P, Poole PJ. (2010) 'Efficiency limiting processes in 1.55 mu m InAs/InP-based quantum dots lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 97 (16) Article number ARTN 161104
  • Sayid SA, Marko IP, Cannard PJ, Chen X, Rivers LJ, Lealman IF, Sweeney SJ. (2010) 'Thermal Characteristics of 1.55-mu m InGaAlAs Quantum Well Buried Heterostructure Lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF QUANTUM ELECTRONICS, 46 (5), pp. 700-705.
  • Pearce JV, Ongrai O, Machin G, Sweeney SJ. (2010) 'Self-validating thermocouples based on high temperature fixed points'. IOP PUBLISHING LTD METROLOGIA, 47 (1), pp. L1-L3.
  • Marko IP, Aldukhayel AM, Adams AR, Sweeney SJ, Teissier R, Baranov AN, Tomić S. (2010) 'Physical properties of short wavelength 2.6μm InAs/AlSb-based quantum cascade lasers'. IEEE Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 95-96.

    Abstract

    We used high hydrostatic pressure techniques to understand the deteriorating temperature performance with decreasing wavelength of short wavelength quantum cascade lasers. Influence of inter-valley scattering and distribution of the electron wave functions will be discussed.

  • Ongrai O, Pearce JV, Machin G, Sweeney SJ. (2010) 'Comparative Study of Pt/Pd and Pt-Rh/Pt Thermocouples'. Springer International Journal of Thermophysics, 31 (8-9), pp. 1506-1516.
  • Crowley MT, Marko IP, Masse NF, Andreev AD, Tomic S, Sweeney SJ, O'Reilly EP, Adams AR. (2009) 'The Importance of Recombination via Excited States in InAs/GaAs 1.3 mu m Quantum-Dot Lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 15 (3), pp. 799-807.
  • Sweeney S. (2009) 'Why not do both?'. Physics World, 22 (12), pp. 44-45.
  • Sweeney SJ, Krause S. (2009) 'Editorial: Selected papers from the second international conference on optical, optoelectronic and photonic materials and applications, 2007'. Springer Journal of Materials Science: Materials in Electronics, 20 (SUPPL. 1), pp. S1-S2.
  • Sweeney SJ, Krause S. (2009) 'Selected Papers from the Second International Conference on Optical, Optoelectronic and Photonic Materials and Applications, 2007'. SPRINGER JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, 20, pp. 1-2.
  • Masse NF, Marko IP, Adams AR, Sweeney SJ. (2009) 'Temperature insensitive quantum dot lasers: are we really there yet?'. SPRINGER JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, London, ENGLAND: 20, pp. 272-276.
  • Coote J, Reddy S, Sweeney SJ. (2009) 'The development of a compact free spectral range semiconductor laser biosensor'. EUROPEAN OPTICAL SOC JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS, 4 Article number ARTN 09013
  • Sharma TK, Hosea TJC, Sweeney SJ, Tang X. (2008) 'An accurate determination of the electronic transitions of InAs/InGaAs/InP quantum dots for midinfrared lasers using simultaneous complementary spectroscopic techniques'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 104 (8) Article number ARTN 083109
  • Chamings J, Adams AR, Sweeney SJ, Kunert B, Volz K, Stolz W. (2008) 'Temperature dependence and physical properties of Ga(NAsP)/GaP semiconductor lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 93 (10) Article number ARTN 101108
  • Chamings J, Ahmed S, Sweeney SJ, Odnoblyudov VA, Tu CW. (2008) 'Physical properties and efficiency of GaNP light emitting diodes'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 92 (2) Article number ARTN 021101
  • Masse NF, Homeyer E, Marko IP, Adams AR, Sweeney SJ, Dehaese O, Piron R, Grillot F, Loualiche S. (2007) 'Temperature and pressure dependence of the recombination processes in 1.5 mu m InAs/InP (311)B quantum dot lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (13) Article number ARTN 131113
  • Coote J, Sweeney SJ. (2007) 'Semiconductor lasers as integrated optical biosensors: Sensitivity optimisation'. Journal of Physics: Conference Series, 76 (1)
  • Masse NF, Adams AR, Sweeney SJ. (2007) 'Experimental determination of the band gap dependence of Auger recombination in InGaAs/InP multiple quantum well lasers at room temperature'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 90 (16) Article number ARTN 161113
  • Ng JS, Soong WM, Steer MJ, Hopkinson M, David JPR, Chamings J, Sweeney SJ, Adams AR. (2007) 'Long wavelength bulk GaInNAs p-i-n photodiodes lattice matched to GaAs'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 101 (6) Article number ARTN 064506
  • Bueckers C, Blume G, Thraenhardt A, Schlichenmaier C, Klar PJ, Weiser G, Koch SW, Hader J, Moloney JV, Hosea TJC, Sweeney SJ, Wang J-B, Johnson SR, Zhang Y-H. (2007) 'Microscopic electroabsorption line shape analysis for Ga(AsSb)/GaAs heterostructures'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 101 (3) Article number ARTN 033118
  • Ng JS, Soong WM, Steer MJ, Hopkinson M, David JPR, Chamings J, Adams AR, Sweeney SJ, Allam J. (2007) 'GaInNAs lattice-matched to GaAs for photodiodes'. Conference Proceedings - International Conference on Indium Phosphide and Related Materials, , pp. 347-349.
  • Jin SR, Ahmad CN, Sweeney SJ, Adams AR, Murdin BN, Page H, Marcadet X, Sirtori C, Tomic S. (2006) 'Spectroscopy of GaAs/AlGaAs quantum-cascade lasers using hydrostatic pressure'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (22) Article number ARTN 221105
  • Masse NF, Sweeney SJ, Marko IP, Adams AR, Hatori N, Sugawara M. (2006) 'Temperature dependence of the gain in p-doped and intrinsic 1.3 mu m InAs/GaAs quantum dot lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (19) Article number ARTN 191118
  • Hild K, Sweeney SJ, Wright S, Lock DA, Jin SR, Marko IP, Johnson SR, Chaparro SA, Yu S-Q, Zhang Y-H. (2006) 'Carrier recombination in 1.3 mu m GaAsSb/GaAs quantum well lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (17) Article number ARTN 173509
  • O'Brien K, Sweeney SJ, Adams AR, Murdin BN, Salhi A, Rouillard Y, Joullie A. (2006) 'Recombination processes in midinfrared InGaAsSb diode lasers emitting at 2.37 mu m'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (5) Article number ARTN 051104
  • O'Brien K, Adams AR, Sweeney SJ, Jin SR, Ahmad CN, Murdin BN, Canedy CL, Vurgaftman I, Meyer JR. (2006) 'Analysis of the major loss processes in mid-infrared type-II "W" diode lasers'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 43-44.
  • Murdin BN, Adams AR, Sweeney SJ. (2006) 'Band structure and high-pressure measurements'. Springer Series in Optical Sciences, 118, pp. 93-127.
  • Marko IP, Masse NF, Sweeney SJ, Andreev AD, Adams AR, Hatori N, Sugawara M. (2005) 'Carrier transport and recombination in p-doped and intrinsic 1.3 mu m InAs/GaAs quantum-dot lasers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 87 (21) Article number ARTN 211114
  • Fehse R, O'Reilly EP, Sweeney SJ, Adams AR, McConville D, Riechert H, Geelhaar L. (2005) 'Investigation of carrier recombination processes and transport properties in GaInAsN/GaAs quantum wells'. American Institute of Physics AIP Conference Proceedings, 772, pp. 985-986.

    Abstract

    It is shown that the dramatic changes in threshold current density with changing active region growth temperature in 1.3μm GaInNAs-based lasers can be attributed almost entirely to changes in the defect related monomolecular recombination current in the optically active material. In addition, growth temperature dependent changes in the QW morphology are shown to have a significant influence on the transport properties of the structure. © 2005 American Institute of Physics.

  • Cripps SA, Hosea TJC, Sweeney SJ, Lock D, Leinonen T, Lyytikainen J, Dumitrescu M. (2005) 'High temperature operation of 760 nm vertical-cavity surface-emitting lasers investigated using photomodulated reflectance wafer measurements and temperature-dependent device studies'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, 152 (2), pp. 103-109.
  • Blume G, Hosea TJC, Sweeney SJ, Johnson SR, Wang JB, Zhang YH. (2005) 'Spectroscopic investigations of GaAsSb/GaAs based structures for 1.3 mu m VCSEL applications'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, 152 (2), pp. 110-117.
  • Blume G, Hosea TJC, Sweeney SJ, de Mierry P, Lancefield D. (2005) 'AlGalnN resonant-cavity LED devices studied by electromodulated reflectance and carrier lifetime techniques'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, 152 (2), pp. 118-124.
  • Hild K, Sweeney SJ, Lock DA, Wright S, Wang JB, Johnson SR, Zhang YH. (2005) 'On the thermal stability of 1.3 mu m GaAsSb/GaAs-based lasers'. IEEE 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), Sydney, AUSTRALIA: , pp. 330-331.
  • Marko IP, Masse N, Sweeney SJ, Adams AR, Sellers IR, Mowbray DJ, Skolnick MS, Liu HY, Groom KM. (2005) 'Effect of gain saturation and nonradiative recombination on the thermal characteristics of InAs/GaAs 1.3 mu m quantum dot lasers'. IEEE 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), Sydney, AUSTRALIA: , pp. 401-402.
  • Masse NF, Marko IP, Sweeney SJ, Adams AR, Hatori N, Sugarawa M. (2005) 'The influence of p-doping on the temperature sensitivity of 1.3 mu m quantum dot lasers'. IEEE 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), Sydney, AUSTRALIA: , pp. 603-604.
  • Jin SR, Sweeney SJ, Ahmad CN, Adams AR, Murdin BN. (2004) 'Radiative and Auger recombination in 1.3 mu m InGaAsP and 1.5 mu m InGaAs quantum-well lasers measured under high pressure at low and room temperatures'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 85 (3), pp. 357-359.
  • Hild K, Sale TE, Sweeney SJ, Hirotani M, Mizuno Y, Kato T. (2004) 'Modulation speed resonant-cavity and leakage current in 650 nm light emitting diodes'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, CARDIFF, WALES: 151 (2), pp. 94-97.
  • Sweeney SJ. (2004) 'Novel experimental techniques for semiconductor laser characterisation and optimisation'. IOP PUBLISHING LTD PHYSICA SCRIPTA, T114, pp. 152-158.
  • Sweeney SJ, Lyons LJ, Adams AR, Lock DA. (2003) 'Direct measurement of facet temperature up to melting point and COD in high-power 980-nm semiconductor diode lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 9 (5), pp. 1325-1332.
  • Jin SR, Sweeney SJ, Tomic S, Adams AR, Riechert H. (2003) 'High-pressure studies of recombination mechanisms in 1.3-mu m GaInNAs quantum-well lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 9 (5), pp. 1196-1201.
  • Knowles G, Fehse R, Tomic S, Sweeney SJ, Sale TE, Adams AR, O'Reilly P, Steinle G, Riechert H. (2003) 'Investigation of 1.3-mu m GaInNAs vertical-cavity surface-emitting lasers (VCSELs) using temperature, high-pressure, and modelling techniques'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 9 (5), pp. 1202-1208.
  • Tomic S, O'Reilly EP, Fehse R, Sweeney SJ, Adams AR, Andreev AD, Choulis SA, Hosea TJC, Riechert H. (2003) 'Theoretical and experimental analysis of 1.3-mu m InGaAsN/GaAs lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 9 (5), pp. 1228-1238.
  • Constant SB, Tomic S, Lock D, Sale TE, Sweeney SJ, Hosea TJC. (2003) 'Spectroscopic characterization of 1450 nm semiconductor pump laser structures for Raman amplifiers'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 93 (12), pp. 9446-9455.
  • Jin SR, Sweeney SJ, Tomic S, Adams AR, Riechert H. (2003) 'Unusual increase of the Auger recombination current in 1.3 mu m GaInNAs quantum-well lasers under high pressure'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 82 (14), pp. 2335-2337.
  • Rice J, Kershaw SV, Dobson P, Oliver RA, Parker MC, Sweeney SJ. (2003) 'Putting nanocrystals to work: from solutions to devices - Discussion'. ROYAL SOC LONDON PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 361 (1803), pp. 340-343.
  • O'Reilly EP, Fahy S, Lindsay A, Tomić S, Fehse R, Adams AR, Sweeney SJ, Andreev AD, Klar PJ, Grüning H, Riechert H. (2003) 'Novel electronic and optoelectronic properties of GaInNAs and related alloys'. OSA Trends in Optics and Photonics Series, 88, pp. 523-525.

    Abstract

    We overview how the novel electronic structure of dilute nitride alloys modifies the gain characteristics of GaInNAs lasers. Optimised devices should have comparable or better characteristics than InP-based emitters, enabling GaAs-based 1.3 μm vertical emitting lasers. ©2000 Optical Society of America.

  • Fehse R, Tomic S, Adams AR, Sweeney SJ, O'Reilly EP, Andreev A, Riechert H. (2002) 'A quantitative study of radiative, Auger, and defect related recombination processes in 1.3-mu m GaInNAs-based quantum-well lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 8 (4), pp. 801-810.
  • Jin SR, Fehse R, Sweeney SJ, Knowles G, Adams AR, O'Reilly EP, Reichert H, Illek S, Egorov AY, Thijs PJA, Uchida T, Fujii T. (2002) 'Modal refractive index of 1.3 mu m InGaAsP, AlGaInAs and GaInNAs semiconductor lasers under high hydrostatic pressure'. IEE-INST ELEC ENG ELECTRONICS LETTERS, 38 (7), pp. 325-327.
  • Knowles G, Fehse R, Tomić S, Sweeney SJ, Sale TE, Adams AR, O'Reilly EP, Steinle G, Riechert H. (2002) 'The temperature and pressure dependence of 1.3 μm GaInNAs vertical-cavity surface emitting lasers (VCSELs)'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 139-140.
  • Sweeney SJ, Lock D, Adams AR, Lyons LJ. (2002) 'Direct measurement of facet temperature up to the melting point and COD in high power 980 nm semiconductor diode lasers'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 161-162.
  • Sweeney SJ, Jin SR, Fehse R, Adams AR, Higashi T, Riechert H, Thijs PJA. (2002) 'A comparison of the thermal stability of InGaAsP, AlGaInAs and GaInNAs quantum-well lasers for 1.3 μm operation'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 43-44.
  • Jin SR, Sweeney SJ, Knowles G, Adams AR, Higashi T, Riechert H, Thijs PJA. (2002) 'Optical investigation of recombination processes in GaInNAs, InGaAsP and AlGaInAs quantum-well lasers using hydrostatic pressure'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 83-84.
  • Tomić S, Fehse R, Choulis SA, Adams AR, Sweeney SJ, Andreev AD, Hosea TJC, O'Reilly EP, Riechert H. (2002) 'Experimental and theoretical analysis of the recombination processes in GaInNAs 1.3 μm Lasers'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 41-42.
  • Fehse R, Jin S, Sweeney SJ, Adams AR, O'Reilly EP, Riechert H, Illek S, Egorov AY. (2001) 'Evidence for large monomolecular recombination contribution to threshold current in 1.3 mu m GaInNAs semiconductor lasers'. IEE-INST ELEC ENG ELECTRONICS LETTERS, 37 (25), pp. 1518-1520.
  • Knowles G, Sweeney SJ, Sale TE, Adams AR. (2001) 'Self-heating effects in red (665 nm) VCSELs'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, 148 (5-6) Article number PII 10.1049/ip-opt:20010843 , pp. 256-260.
  • Sweeney SJ, Knowles G, Sale TE. (2001) 'Evaluating the continuous-wave performance of AlGaInP-based red (667 nm) vertical-cavity surface-emitting lasers using low-temperature and high-pressure techniques'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 78 (7), pp. 865-867.
  • Fehse R, Sweeney SJ, Adams AR, O'Reilly EP, Egorov AY, Riechert H, Illek S. (2001) 'Insights into carrier recombination processes in 1.3 mu m GaInNAs-based semiconductor lasers attained using high pressure'. IEE-INST ELEC ENG ELECTRONICS LETTERS, 37 (2), pp. 92-93.
  • Sweeney SJ, Knowles G, Sale TE, Adams AR. (2001) 'Quantifying the effect of indirect carrier leakage on visible Al(GaInP) lasers using high pressures and low temperatures'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 223 (2), pp. 567-572.
  • Sale TE, Sweeney SJ, Knowles G, Adams AR. (2001) 'Gain-cavity alignment in efficient visible (660 nm) VCSELs studied using high pressure techniques'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 223 (2), pp. 587-591.
  • Knowles G, Sweeney SJ, Sale TE, Adams AR. (2001) 'Assessing the performance of visible (665 nm) vertical cavity surface emitting lasers using high pressure and low temperature techniques'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 223 (2), pp. 581-585.
  • Sweeney SJ, Higashi T, Andreev A, Adams AR, Uchida T, Fujii T. (2001) 'Superior temperature performance of 1.3 mu m AlGaInAs-Based semiconductor lasers investigated at high pressure and low temperature'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 223 (2), pp. 573-579.
  • Sale TE, Knowles GC, Sweeney SJ, Onischenko A, Frost JEF, Pinches SM, Woodhead J. (2000) '-180 to +80 degrees C CW lasing in visible VCSELs'. IEEE 2000 IEEE 17TH INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, CONFERENCE DIGEST, MONTEREY, CA: , pp. 15-16.
  • Sweeney SJ, Adams AR, O'Reilly EP, Silver M, Thijs PJA. (2000) 'Effect of auger generated hot-holes on 1.5-μm InGaAs(P)-based quantum well semiconductor lasers'. Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, , pp. 391-392.
  • Phillips AF, Sweeney SJ, Adams AR, Thijs PJA. (1999) 'The temperature dependence of 1.3-and 1.5-mu m compressively strained InGaAs(P) MQW semiconductor lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 5 (3), pp. 401-412.
  • Higashi T, Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Uchida T, Fujii T. (1999) 'Experimental analysis of temperature dependence in 1.3-mu m AlGaInAs-InP strained MQW lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 5 (3), pp. 413-419.
  • Higashi T, Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Uchida T, Fujii T. (1999) 'Observation of reduced nonradiative current in 1.3-mu m AlGaInAs-InP strained MQW lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE PHOTONICS TECHNOLOGY LETTERS, 11 (4), pp. 409-411.
  • Sweeney SJ, Higashi T, Adams AR, Uchida T, Fujii T. (1998) 'Improved temperature dependence of 1.3 mu m AlGalnAs-based MQW semiconductor diode lasers revealed by hydrostatic pressure'. IEE-INST ELEC ENG ELECTRONICS LETTERS, 34 (22), pp. 2130-2132.
  • Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Thijs PJA. (1998) 'The effect of temperature dependent processes on the performance of 1.5-mu m compressively strained InGaAs(P) MQW semiconductor diode lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE PHOTONICS TECHNOLOGY LETTERS, 10 (8), pp. 1076-1078.
  • Higashi T, Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Uchida T, Fujii T. (1998) 'Observation of reduced non-radiative recombination current in 1.3-μm AlGaInAs/InP multiple-quantum-well lasers'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 61-62.
  • Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Thijs PJA. (1998) 'Determination of the influence of Auger recombination on the threshold current of 1.3 μm and 1.5 μm InGaAs(P) strained-layer lasers and its variation with temperature'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 63-64.
  • Sweeney SJ, Phillips AF, Adams AR, O'Reilly EP, Silver M, Thijs PJA. (1998) 'Transition from radiative to nonradiative recombination in 1.3-μm and 1.5-μm InGaAs(P) multiple quantum well semiconductor diode lasers'. Conference on Lasers and Electro-Optics Europe - Technical Digest, , pp. 304-304.

Conference papers

  • Hosea TJC, Chai GMT, Marko IP, Batool Z, Hild K, Jin SR, Hossain N, Sweeney SJ, Petropoulos JP, Zhong Y, Dongmo PB, Zide JMO. (2012) 'InGaBiAs/InP semiconductors for mid-infrared applications: Dependence of bandgap and spin-orbit splitting on temperature and bismuth content'. ICP 2012 - 3rd International Conference on Photonics 2012, Proceedings, , pp. 154-158.
  • Sweeney SJ, Batool Z, Hild K, Jin SR, Hosea TJC. (2011) 'The Potential Role of Bismide Alloys in Future Photonic Devices'. IEEE 13TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, Stockholm, Sweden: 13th ICTON
  • Hossain N, Jin SR, Sweeney SJ, Liebich S, Ludewig P, Zimprich M, Volz K, Kunert B, Stolz W. (2011) 'Physical properties of monolithically integrated Ga(NAsP)/(BGa)P QW lasers on silicon'. IEEE 8th IEEE International Conference on Group IV Photonics, London, UK: Group IV Photonics, pp. 148-150.
  • Lever L, Hu Y, Myronov M, Liu X, Owens N, Gardes FY, Marko IP, Sweeney SJ, Ikonić Z, Leadley DR, Reed GT, Kelsall RW. (2011) 'Strain engineering of the electroabsorption response in Ge/SiGe multiple quantum well heterostructures'. IEEE 8th IEEE International Conference on Group IV Photonics, London, UK: Group IV Photonics, pp. 107-108.
  • Hossain N, Chamings J, Jin SR, Sweeney SJ, Liebich S, Reinhard S, Volz K, Kunert B, Stolz W. (2010) 'Recombination and loss mechanisms in GaNAsP/GaP QW lasers'. Proceedings of Photonics Global Conference, Orchard, Singapore: PGC 2010

    Abstract

    In this paper the authors present a comprehensive study of the threshold current and its temperature dependence in novel direct band-gap Ga(NAsP)/GaP QW lasers which provide a potential route to lattice matched monolithic integration of long term stable semiconductor lasers on silicon. It is found that near room temperature, the threshold current is dominated by nonradiative recombination accounting for ~87% of the total threshold current density. A strong increase in threshold current with hydrostatic pressure implies that a carrier leakage path is the dominant carrier recombination mechanism.

  • Ongrai O, Pearce JV, Machin G, Sweeney SJ. (2010) 'Comparative Study of Pt/Pd and Pt-Rh/Pt Thermocouples'. SPRINGER/PLENUM PUBLISHERS INTERNATIONAL JOURNAL OF THERMOPHYSICS, Portoroz, SLOVENIA: 1st TEMPMEKO and ISHM Joint International Symposium on Temperature, Humidity, Moisture, and Thermal Measurements 31 (8-9), pp. 1506-1516.
  • Sayid SA, Marko IP, Cannard PJ, Chen X, Rivers LJ, Lealman IF, Sweeney SJ. (2010) 'Thermal performance of 1.55μm InGaAlAs quantum well buried heterostructure lasers'. IEEE Proceedings of 22nd International Conference on Indium Phosphide and Related Materials, Kagawa, Japan: 22nd IPRM, pp. 265-268.

    Abstract

    We have investigated the threshold current Ith and differential quantum efficiency as the function of temperature in InGaAlAs/InP multiple quantum well (MQWs) buried heterostructure (BH) lasers. We find that the temperature sensitivity of Ith is due to non-radiative recombination which accounts for up to ~80% of Jth at room temperature. Analysis of spontaneous emission emitted from the devices show that the dominant non-radiative recombination process is consistent with Auger recombination. We further show that the above threshold differential internal quantum efficiency, ηi, is ~80% at 20°C remaining stable up to 80°C. In contrast, the internal optical loss, αi, increases from 15 cm-1 at 20°C to 22 cm-1 at 80°C, consistent with inter-valence band absorption (IVBA). This suggests that the decrease in power output at elevated temperatures is associated with both Auger recombination and IVBA.

  • Sayid SA, Marko IP, Sweeney SJ, Poole P. (2010) 'Temperature sensitivity of 1.55μm (100) InAs/InP-based quantum dot lasers'. IEEE Proceedings of 22nd International Conference on Indium Phosphide and Related Materials, Kagawa, Japan: 22nd IPRM, pp. 23-24.

    Abstract

    Semiconductor lasers with quantum dot (QD) based active regions have generated a huge amount of interest for applications including communications networks due to their anticipated superior physical properties due to three dimensional carrier confinement. For example, the threshold current of ideal quantum dots is predicted to be temperature insensitive. We have investigated the operating characteristics of 1.55 μm InAs/InP (100) quantum dot lasers focusing on their carrier recombination characteristics using a combination of low temperature and high pressure measurements. By measuring the intrinsic spontaneous emission from a window fabricated in the n-contact of the devices we have measured the radiative component of the threshold current density, Jrad. We find that Jrad is itself relatively temperature insensitive (Fig. 1). However, the total threshold current density, Jth, increases significantly with temperature leading to a characteristic temperature T0~72 K around 220 K-290 K. From this data it is clear that the devices are dominated by a non-radiative recombination process which accounts for up to 94% of the threshold current at room temperature (Fig. 1).

  • Liebich S, Zimprich M, Ludewig P, Beyer A, Volz K, Stolz W, Kunert B, Hossain N, Jin SR, Sweeney SJ. (2010) 'MOVPE growth and characterization of Ga(NAsP) laser structures monolithically integrated on Si (001) substrates'. 22nd IEEE International Semiconductor Laser Conference, Kyoto, Japan: 22nd IEEE ISLC, pp. 143-144.
  • Ikyo BA, Marko IP, Adams AR, Sweeney SJ, Canedy CL, Vurgaftman I, Kim CS, Kim M, Bewley WW, Meyer JR. (2010) 'Temperature sensitivity of mid-infrared type II "W" interband cascade lasers (ICL) emitting at 4.1μm at room temperature'. IEEE 22nd IEEE International Semi-conductor Laser Conference, Kyoto, Japan: ISLC 2010, pp. 41-42.
  • Sweeney SJ. (2010) 'Bismide-alloys for higher efficiency infrared semiconductor lasers'. IEEE 22nd IEEE International Semiconductor Laser Conference, Kyoto, Japan: ISLC 2010, pp. 111-112.
  • Sayid SA, Marko IP, Adams AR, Sweeney SJ, Barrios P, Poole P. (2010) 'Thermal behavior of 1.55 μm (100) InAs/InP-based quantum dot lasers'. IEEE Poceeedings of 22nd International Semiconductor Laser Conference, Kyoto, Japan: ISLC 2010, pp. 75-76.
  • Hossain N, Jin SR, Sweeney SJ, Liebich S, Ludewig P, Zimprich M, Kunert B, Volz K, Stolz W. (2010) 'Lasing properties of monolithically integrated Ga(NAsP)/(BGa)P QW lasers on a Silicon substrate grown by MOVPE'. 22nd IEEE International Semiconductor Laser Conference, Kyoto, Japan: 22nd IEEE ISLC, pp. 109-110.
  • Hossain N, Hild K, Jin S, Sweeney SJ, Yu S-Q, Johnson SR, Ding D, Zhang Y-H. (2010) 'Role of growth temperature on the physical characteristics of GaAsSb/GaAs QW lasers'. IEEE 23rd Annual Meeting of the IEEE Photonics Society, Denver, USA: Photonics 2010, pp. 59-60.
  • Ng JS, Tan SL, Goh YL, Tan CH, David JPR, Allam J, Sweeney SJ, Adams AR. (2010) 'InGaAsN as absorber in APDs for 1.3 micron wavelength applications'. Kagawa, Japan: IPRM 2010, pp. 187-190.

    Abstract

    Two issues with using InGaAsN as absorber in avalanche photodiodes (APDs) for 1310nm wavelength applications are addressed here. Firstly, we demonstrated InGaAsN p-i-n diodes with stable photoresponse around 1310nm but reverse leakage current density slightly above the acceptable limit of ~0.2mA/cm2 at 150kV/cm. We also investigated whether or not InGaAsN as absorber is compatible with Al0.8Ga0.2As (the proposed avalanche material in our separate-absorption-multiplication APD design) in terms of the relationship between α and β in InGaAsN. Our observations suggest α ~ β in InGaAsN, making it compatible with Al0.8Ga0.2As.

  • Tan SL, Tan LJJ, Goh YL, Zhang S, Ng JS, David JPR, Marko IP, Allam J, Sweeney SJ, Adams AR. (2010) 'Reduction of dark current and unintentional background doping in InGaAsN photodetectors by ex situ annealing'. SPIE Proceedings of SPIE - Posters Session, Brussels, Belgium: Optical Sensing and Detection 7726

    Abstract

    InGaAsN is a promising material system to enable low-cost GaAs-based detectors to operate in the telecommunication spectrum, despite the problems posed by the low growth temperature required for nitrogen incorporation. We demonstrate that InGaAsN p+-i-n+ structures with nominal In and N fraction of 10% and 3.8%, grown by molecular beam epitaxy (MBE) under non-optimal growth conditions, can be optimized by post growth thermal annealing to match the performance of optimally grown structures. We report the findings of an annealing study by comparing the photoluminescence spectra, dark current and background concentration of the as-grown and annealed samples. The dark current of the optimally annealed sample is approximately 2 μA/cm2 at an electric field of 100 kV/cm, and is the lowest reported to date for InGaAsN photodetectors with a cut-off wavelength of 1.3 μm. Evidence of lower unintentional background concentration after annealing at a sufficiently high temperature, is also presented.

  • Hossain N, Jin SR, Sweeney SJ, Liebich S, Reinhard S, Volz K, Kunert B, Stolz W. (2010) 'Physical properties of Ga(NAsP)/GaP QW lasers grown by MOVPE'. IEEE 23rd Annual Meeting of the IEEE Photonics Society, Denver, USA: Photonics 2010, pp. 65-66.
  • Hossain N, Jin SR, Sweeney SJ, Yu S-Q, Johnson SR, Ding D, Zhang Y-H, Belyanin AA, Smowton PM. (2010) 'Improved Performance of GaAsSb/GaAs SQW Lasers'. SPIE-INT SOC OPTICAL ENGINEERING NOVEL IN-PLANE SEMICONDUCTOR LASERS IX, San Francisco, CA: Conference on Novel In - Plane Semiconductor Lasers IX 7616
  • Hossain N, Hild K, Jin SR, Sweeney SJ, Yu S-Q, Johnson SR, Ding D, Zhang Y-H. (2010) 'Influence of device structures on carrier recombination in GaAsSb/GaAs QW lasers'. Proceedings of Photonics Global Conference, Orchard, Singapore: PGC 2010

    Abstract

    We investigate the temperature and pressure dependence of carrier recombination processes occurring in various GaAsSb/GaAs QW laser structures grown under similar growth conditions. Thermally activated carrier leakage via defects is found to be very sensitive to the strain induced interface imperfections. Nonradiative recombination is found to be sensitive to the number of QWs. A strain compensated MQW structure leads to a reduced contribution of non-radiative recombination to the threshold current density (Jth) and a high characteristic temperature (T0) of 73K at room temperature.

  • Crutchley BG, Marko IP, Adams AR, Sweeney SJ. (2010) 'Efficiency limitations of green InGaN LEDs and laser diodes'. 22nd IEEE International Semiconductor Laser Conference, Kyoto, Japan: ISLC 2010, pp. 27-28.
  • Ikyo AB, Marko IP, Adams AR, Sweeney SJ, Bachmann A, Kashani-Shirazi K, Amann M-C. (2009) 'Gain peak-cavity mode alignment optimisation in buried tunnel junction mid-infrared GaSb vertical cavity surface emitting lasers using hydrostatic pressure'. INST ENGINEERING TECHNOLOGY-IET IET OPTOELECTRONICS, Cardiff, WALES: Semiconductor and Integrated Optoelectronics Conference (SIOE 2009) 3 (6), pp. 305-309.
  • Marko IP, Ikyo AB, Adams AR, Sweeney SJ, Bachmann A, Kashani-Shirazi K, Amann M-C. (2009) 'Band-structure and gain-cavity tuning of 2.4-μm GaSb buried tunnel junction VCSELs'. Proceedings of European Conference on Lasers and Electro-Optics 2009 and the European Quantum Electronics Conference, Munich, Germany: CLEO Europe - EQEC 2009

    Abstract

    Low-cost, continuous-wave GaSb-based vertical cavity surface emitting lasers (VCSELs) operating at ~ 2.4 mum up to 50degC have been demonstrated recently. In this work we have used high pressure techniques to investigate ways to improve their performance and extend their working temperature range. Since the band-gap and energy of the gain peak (Ep) increase with pressure at 0.126 meV/MPa at constant temperature, when applied to edge emitting lasers (EEL) we can use pressure to determine the radiative and non-radiative recombination processes occurring. In the VCSEL the pressure dependence of the threshold current, is much more complicated. At the higher temperature the decreasing Auger recombination initially dominates. Therefore we predict that either increasing the band gap or increasing the operating wavelength will allow an improved temperature performance of these GaSb-based VCSELs.

  • Fox NE, Sharma TK, Sweeney SJ, Hosea TJC. (2009) 'Room temperature characterisation of InGaAlAs quantum well laser structures using electro-modulated reflectance and surface photovoltage spectroscopy'. WILEY-BLACKWELL PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, Wroclaw Univ Technol, Wroclaw, POLAND: 3rd International Workshop on Modulation Spectroscopy of Semiconductor Structures 206 (5), pp. 796-802.
  • Chamings J, Ahmed S, Adams AR, Sweeney SJ, Odnoblyudov VA, Tu CW, Kunert B, Stolz W. (2009) 'Band anti-crossing and carrier recombination in dilute nitride phosphide based lasers and light emitting diodes'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Fortaleza, BRAZIL: 13th International Conference on High Pressure Semiconductor Physics (HPSP-13) 246 (3), pp. 527-531.
  • Marko IP, Adams AR, Sweeney SJ, Teissier R, Baranov AN, Tomic S. (2009) 'Evidence of carrier leakage into the L-valley in InAs-based quantum cascade lasers under high hydrostatic pressure'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Fortaleza, BRAZIL: 13th International Conference on High Pressure Semiconductor Physics (HPSP-13) 246 (3), pp. 512-515.
  • Adams AR, Marko IP, Sweeney SJ, Teissier R, Baranov AN, Tomić S. (2009) 'The effect of hydrostatic pressure on the operation of quantum cascade lasers'. SPIE Proceedings of SPIE - Quantum Cascade Lasers and Applications I, San Jose, USA: Quantum Sensing and Nanophotonic Devices VI 7222

    Abstract

    Quantum Cascade Lasers (QCLs) have been very successful at long wavelengths, >4μm, and there is now considerable effort to develop QCLs for short wavelength (2-3μm) applications. To optimise both interband and QC lasers it is important to understand the role of radiative and non-radiative processes and their variation with wavelength and temperature. We use high hydrostatic pressure to manipulate the band structure of lasers to identify the dominant efficiency limiting processes. We describe how hydrostatic pressure may also be used to vary the separation between the Γ, Χ and L bands, allowing one to investigate the role of inter-valley carrier scattering on the properties of QCLs. We will describe an example of how pressure can be used to investigate the properties of 2.9-3.3μm InAs/AlSb QCLs. We find that while the threshold current of the 3.3μm devices shows little pressure variation even at room temperature, for the 2.9μm devices the threshold current increases by ~20% over 4kbar at 190K consistent with carrier scattering into the L-minima. Based on our high pressure studies, we conclude that the maximum operating temperature of InAs/AlSb QCLs decreases with decreasing wavelength due to increased carrier scattering into the L-minima of InAs.

  • Tan LJJ, Soong WS, Tan SL, Goh YL, Steer MJ, Ng JS, David JPR, Marko IP, Chamings J, Allam J, Sweeney SJ, Adams AR. (2009) 'Dark current mechanisms in InxGa1-xAs 1-yNy'. IEEE IEEE Proceedings of LEOS Annual Meeting Conference, Belek-Antalya, Turkey: LEOS '09, pp. 233-234.
  • Crowley MT, Marko IP, Masse NF, Andreev AD, Sweeney SJ, O'Reilly EP, Adams AR. (2008) 'The importance of recombination via excited states in InAs/GaAs 1.3μm quantum dot lasers'. IEEE IEEE Proceedings of 21st International Semiconductor Laser Conference, Sorento, Italy: 21st ISLC 2008, pp. 117-118.
  • Green BC, Yu S-Q, Sweeney SJ, Ding D, Zhang Y-H. (2008) 'Novel heterostructure design for increased spectral width of superluminescentdiodes and dual-wavelength laser diodes'. Device Research Conference - Conference Digest, Santa Barbara, USA: 66th DRC, pp. 309-310.
  • Lealman I, Dosanjh S, Rivers L, O'Brien S, Cannard P, Sweeney SJ, Marko IP, Rushworth S. (2008) 'Reliable 1550nm SI BH lasers fabricated using an improved Ru precursor'. 20th International Conference on Indium Phosphide and Related Materials, Versailles, France: IPRM 2008
  • Chamings J, Adams AR, Sweeney SJ, Kunert B, Volz K, Stolz W. (2008) 'Thermal properties of Silicon compatible GaNAsP SQW lasers'. IEEE 2008 IEEE 21ST INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, Sorrento, ITALY: IEEE 21st International Semiconductor Laser Conference, pp. 61-62.
  • Sweeney SJ, Hild K, Marko IP, Yu S-Q, Johnson SR, Zhang Y-H. (2008) 'Thermal characteristics of 1.3 mu m GaAsSb/GaAs-based Edge- and Surface-emitting Lasers'. IEEE 2008 IEEE 21ST INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, Sorrento, ITALY: IEEE 21st International Semiconductor Laser Conference, pp. 83-84.
  • Tu CW, Odnoblyudov VA, Chamings J, Ahmed S, Sweeney SJ, Keogh DM. (2008) 'Materials and light-emitting diode properties of dilute-nitride GaNP/GaP heterostructures'. Device Research Conference - Conference Digest, Santa Barbara, USA: 66th DRC, pp. 299-300.
  • Marko IP, Adams AR, Sweeney SJ, Teissier R, Baranov AN, Tomic S. (2008) 'Gamma-L scattering in InAs-based quantum cascade lasers studied using high hydrostatic pressure'. IEEE 2008 IEEE 21ST INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, Sorrento, ITALY: IEEE 21st International Semiconductor Laser Conference, pp. 47-48.
  • Soong WM, Ng JS, Steer MJ, Hopkinson M, David JPR, Chamings J, Sweeney SJ, Adams AR, Allam J. (2008) 'Dark current mechanisms in bulk GaInNAs photodiodes'. IEEE Proccedings of 20th International Conference on Indium Phosphide and Related Materials, Versailles, France: IPRM 2008

    Abstract

    We have grown a series of bulk GaInNAs p-i-n diodes and identified some of the dark current mechanisms present in our devices. With a nitrogen composition of ~4 %, the band gap can be reduced to 0.94 eV. We also demonstrate that low dark current density is achievable without compromising the absorption and hence quantum efficiency up to 1.4 mum.

  • Coote J, Reddy S, Sweeney SJ. (2007) 'Optimisation of distributed feedback laser biosensors'. INST ENGINEERING TECHNOLOGY-IET IET OPTOELECTRONICS, Cardiff, WALES: 21st Conference on Semiconductor Integrated Optoelectronics (SIOE) 1 (6), pp. 266-271.
  • Marko IP, Masse NF, Sweeney SJ, Adams AR, Hatori N, Sugawara M, Jantsch W, Schaffler F. (2007) 'Recombination, transport and loss mechanisms in p-doped InAs/GaAs quantum dots'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 837-838.
  • Marko IP, Adams AR, Sweeney SJ, Masse NF, Krebs R, Reithmaier JP, Forchel A, Mowbray DJ, Skolnick MS, Liu HY, Groom KM, Hatori N, Sugawara M. (2007) 'Band gap dependence of the recombination processes in InAs/GaAs quantum dots studied using hydrostatic pressure'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 82-86.
  • Hild K, Sweeney SJ, Marko IP, Jin SR, Johnson SR, Chaparro SA, Yu S, Zhang Y-H. (2007) 'Temperature and pressure dependence of carrier recombination processes in GaAsSb/GaAs quantum well lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 197-202.
  • Hild K, Sweeney SJ, Jin SR, Healy SB, O'Reilly EP, Johnson SR, Wang J-B, Zhang Y-H. (2007) 'Band alignment and carrier recombination in GaAsSb/GaAs quantum wells'. AIP Conference Proceedings, 893, pp. 1431-1432.

    Abstract

    Using a combination of experimental and theoretical techniques, we investigated the band alignment and the carrier recombination processes occurring in GaAsSb/GaAs structures. We find that for Sb fractions ∼30%, the band alignment is slightly type II. From studies on lasers based upon this material we show that at the high carrier densities required to achieve threshold, at room temperature, the devices are dominated by carrier leakage and non-radiative Auger recombination. © 2007 American Institute of Physics.

  • McConville DG, Sweeney SJ, Adams AR, Tomic S, Riechert H. (2007) 'Temperature and pressure dependence of the recombination mechanisms in 1.3 pm and 1.5 pm GaInNAs lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 208-212.
  • Marko IP, Adams AR, Sweeney SJ, Whitbread ND, Ward AJ, Asplin B, Robbins DJ. (2007) 'The influence of carrier density non-pinning on the output power of 1.55 μm lasers at high temperature'. Conference on Lasers and Electro-Optics Europe - Technical Digest,
  • O'Brien K, Adams AR, Sweeney SJ, Jin SR, Ahmad CN, Murdin BN, Canedy CL, Vurgaftman I, Meyer JR. (2007) 'High pressure studies of mid-infrared type-II "W" diode lasers at cryogenic temperatures'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 224-228.
  • O'Brien K, Sweeney SJ, Adams AR, Jin SR, Ahmad CN, Murdin BN, Salhi A, Rouillard Y, Joullie A. (2007) 'Carrier recombination mechanisms in mid-infrared GaInAsSb quantum well lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 203-207.
  • Massé NF, Sweeney SJ, Marko IP, Andreev AD, Adams AR, Hatori N, Sugawara M. (2006) 'Intrinsic limitations of p-doped and undoped 1.3 μm InAs/GaAs quantum dot lasers'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 143-144.
  • Adams AR, Sweeney SJ. (2006) 'The physics controlling the sensitivity of semiconductor lasers to high temperatures'. OPTICAL SOC AMERICA 2006 OPTICAL FIBER COMMUNICATION CONFERENCE/NATIONAL FIBER OPTIC ENGINEERS CONFERENCE, VOLS 1-6, Anaheim, CA: Conference on Optical Fiber Communications/National Fiber Optic Engineers Conference, pp. 1631-1633.
  • Marko IP, Adams AR, Sweeney SJ, Mowbray DJ, Skolnick MS, Liu HYY, Groom KM. (2005) 'Recombination and loss mechanisms in low-threshold InAs-GaAs 1.3-mu m quantum-dot lasers'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, Matsue, JAPAN: 19th IEEE International Semiconductor Laser Conference 11 (5), pp. 1041-1047.
  • Blume G, Hosea TJC, Sweeney SJ. (2005) 'A study of the low-energy interference oscillations in photoreflectance of GaAsSb/GaAs quantum well structures'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, Wroclaw, POLAND: International Workshop on Modulation Spectroscopy of Semiconductor Structures 202 (7), pp. 1244-1254.
  • Sweeney SJ, Lock DA, Adams AR, Menendez J, VanDeWalle CG. (2005) 'Carrier recombination in InGaAs(P) quantum well laser structures: Band gap and temperature dependence'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Flagstaff, AZ: 27th International Conference on the Physics of Semiconductors (ICPS-27) 772, pp. 1545-1546.
  • Marko IP, Andreev AD, Sweeney SJ, Adams AR, Krebs R, Deubert S, Reithmaier JP, Forchel A, Menendez J, VanDeWalle CG. (2005) 'The influence of auger processes on recombination in long-wavelength InAs/GaAs quantum dots'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Flagstaff, AZ: 27th International Conference on the Physics of Semiconductors (ICPS-27) 772, pp. 681-682.
  • Sweeney SJ, Jin SR, Ahmad CN, Adams AR, Murdin BN. (2004) 'Carrier recombination processes in 1.3 mu m and 1.5 mu m InGaAs(P)-based lasers at cryogenic temperatures and high pressures'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, Berkeley, CA: 11th International Conference on High-Pressure Semiconductor Physics (HPSP-11) 241 (14), pp. 3399-3404.
  • Lock D, Sweeney SJ, Adams AR. (2004) 'Pressure induced wavelength dependence of catastrophic optical damage in 980 nm semiconductor diode lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, Berkeley, CA: 11th International Conference on High-Pressure Semiconductor Physics (HPSP-11) 241 (14), pp. 3416-3419.
  • Marko IP, Sweeney SJ, Adams AR, Jin SR, Murdin BN, Schwertberger R, Somers A, Reithmaier JP, Forchel A. (2004) 'Recombination mechanisms in InAs/InP quantum dash lasers studied using high hydrostatic pressure'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, Berkeley, CA: 11th International Conference on High-Pressure Semiconductor Physics (HPSP-11) 241 (14), pp. 3427-3431.
  • Sweeney SJ, McConville D, Masse NF, Bouyssou RX, Adams AR, Ahmad CN, Hanke C. (2004) 'Temperature and pressure dependence of recombination processes in 1.5 mu m InGaAlAs/InP-based quantum well lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, Berkeley, CA: 11th International Conference on High-Pressure Semiconductor Physics (HPSP-11) 241 (14), pp. 3391-3398.
  • Lock D, Sweeney SJ, Adams AR, Deubner S, Klopf F, Reithmaier JP, Forchel A. (2004) 'Carrier leakage suppression utilising short-period superlattices in 980 nm InGaAs/GaAs quantum well lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, Berkeley, CA: 11th International Conference on High-Pressure Semiconductor Physics (HPSP-11) 241 (14), pp. 3405-3409.
  • Fehse R, Sweeney SJ, Adams AR, McConville D, Riechert H, Geelhaar L. (2004) 'Influence of growth temperature on carrier recombination in GaInNAs-based lasers'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, Strasbourg, FRANCE: Symposium on Dilute Nitride and Related Mismatched Semiconductor Alloys held at the 2004 Spring Meeting of the EMRS 151 (5), pp. 447-451.
  • Fehse R, Sweeney SJ, Adams AR, McConville D, Riechert H, Geelhaar L. (2004) 'Influence of growth temperature on defect density in 1.3 mu m GaInNAs-based lasers'. IEEE 2004 IEEE 19TH INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, CONFERENCE DIGEST, Matsue, JAPAN: 19th IEEE International Semiconductor Laser Conference, pp. 85-86.
  • Marko IP, Adams AR, Sweeney SJ, Sellers IR, Mowbray DJ, Skolnick MS, Liu HY, Groom KM, Messe K. (2004) 'Recombination and loss mechanisms in low-threshold InAs/GaAs 1.3 mu m quantum dot lasers'. IEEE 2004 IEEE 19TH INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, CONFERENCE DIGEST, Matsue, JAPAN: 19th IEEE International Semiconductor Laser Conference, pp. 57-58.
  • Marko IP, Adams AR, Sweeney SJ, Jin SR, Murdin BN, Schwertberger R, Somers A, Reithmaier JP, Forchel A, Messe K. (2004) 'Experimental investigations into the thermal properties of 1.5-1.8-mu m InAs/InP quantum dash lasers'. IEEE 2004 IEEE 19TH INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE, CONFERENCE DIGEST, Matsue, JAPAN: 19th IEEE International Semiconductor Laser Conference, pp. 61-62.
  • Sweeney SJ, McConville D, Jin SR, Ahmad CN, Masse NF, Bouyssou RX, Adams AR, Hanke C. (2004) 'Temperature and wavelength dependence of recombination processes in 1.5 mu m InGaAlAs/InP-based lasers'. IEEE 2004 International Conference on Indium Phosphide and Related Materials, Conference Proceedings, Kagoshima, JAPAN: 16th International Conference on Indium Phosphide and Related Materials, pp. 738-741.
  • Fehse R, Adams AR, Sweeney SJ, Tomic S, Reichart H, Ramakrishnan A. (2003) 'Carrier recombination processes in MOVPE and MBE grown 1.3 mu m GaInNAs edge emitting lasers'. PERGAMON-ELSEVIER SCIENCE LTD SOLID-STATE ELECTRONICS, STRASBOURG, FRANCE: Spring Meeting of the European-Materials-Research-Society (E-MRS) 47 (3), pp. 501-506.
  • Jin SR, Sweeney SJ, Adams AR, Higashi T, Riechert H, Thijs PJA. (2003) 'Wavelength dependence of the modal refractive index in 1.3 mu m InGaAsP, AlGaInAs and GaInNAs lasers using high pressure'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 491-495.
  • Jin SR, Sweeney SJ, Adams AR, Thijs PJA. (2003) 'Coupling of large optical loss with Auger recombination in 1.3 mu m InGaAsP lasers investigated using hydrostatic pressure'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 547-551.
  • Knowles G, Tomic S, Jin S, Fehse R, Sweeney SJ, Sale TE, Adams AR. (2003) 'Gain-cavity alignment profiling of 1.3 mu m emitting GaInNAs vertical cavity surface emitting lasers (VCSELs) using high pressure techniques'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 480-485.
  • Lock D, Sweeney SJ, Adams AR, Robbins DJ. (2003) 'Auger recombination in InGaAs/AlGaAs-based MQW semiconductor lasers emitting at 980 nm'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 542-546.
  • Sweeney SJ, Jin SR, Tomic S, Adams AR, Higashi T, Riechert H, Thijs PJA. (2003) 'Hydrostatic pressure dependence of recombination mechanisms in GaInNAs, InGaAsP and AlGaInAs 1.3 mu m quantum well lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 474-479.
  • Jin SR, Sweeney SJ, Tomic S, Adams AR, Riechert H. (2003) 'Quantifying pressure-dependent recombination currents in GaInNAs lasers using spontaneous emission measurements'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, UNIV SURREY, GUILDFORD, ENGLAND: 10th International Conference on High Pressures in Semiconductor Physics (HPSP-X) 235 (2), pp. 486-490.
  • Lock D, Sweeney SJ, Adams AR. (2003) 'Wavelength dependence of catastrophic optical damage threshold in 980nm semiconductor diode lasers'. IEEE 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2, TUCSON, AZ: 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp. 421-422.
  • Sweeney SJ, Thijs PJA. (2003) 'Origin of the high temperature performance degradation of 1.5 mu m InGaAs(P)/InP quantum well lasers'. IEEE 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2, TUCSON, AZ: 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp. 977-978.
  • Sweeney SJ, Fehse R, Adams AR, Riechert H. (2003) 'Intrinsic temperature sensitivities of 1.3 mu m GaInNAs/GaAs, InGaAsP/InP and AlGaInAs/InP-based semiconductor lasers'. IEEE 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2, TUCSON, AZ: 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp. 39-40.
  • Lock D, Sweeney SJ, Adams AR. (2003) 'Fundamental limitations of high power 980nm InGaAs/GaAs pump lasers'. IEEE 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2, TUCSON, AZ: 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp. 427-428.
  • Adams AR, Fehse R, Tomic S, O'Reilly EP, Andreev A, Knowles G, Sale TE, Sweeney SJ, Steinle G, Ramakrishnan A, Riechert H, ChangHasnain CJ, Xia YX, Iga K. (2002) 'Characterisation of 1.3pm wavelength GaInNAs/GaAs edge-emitting and vertical-cavity surface-emitting lasers using low-temperature and high-pressure'. SPIE-INT SOC OPTICAL ENGINEERING APOC 2002: ASIA-PACIFIC OPTICAL AND WIRELESS COMMUNICATIONS; MATERIALS AND DEVICES FOR OPTICAL AND WIRELESS COMMUNICATIONS, SHANGHAI, PEOPLES R CHINA: Conference on Asia-Pacific Optical and Wireless Communication (APOC 2002) 4905, pp. 183-197.
  • Knowles G, Sweeney SJ, Sale T. (2001) 'Influence of leakage and gain-cavity alignment on the performance of Al(GaInP) visible vertical-cavity surface emitting lasers'. IEE-INST ELEC ENG IEE PROCEEDINGS-OPTOELECTRONICS, CARDIFF, WALES: Conference on Semiconductor Optoelectronics 148 (1), pp. 55-59.
  • Fehse R, Jin S, Sweeney SJ, Adams AR, O'Reilly EP, Illek S, Egorov AY, Riechert H. (2001) 'The temperature dependence of the recombination processes in 1.3 mu m GaInNAs-based edge emitting lasers'. IEEE LEOS 2001: 14TH ANNUAL MEETING OF THE IEEE LASERS & ELECTRO-OPTICS SOCIETY, VOLS 1 AND 2, PROCEEDINGS, SAN DIEGO, CA: 14th Annual Meeting of the IEEE Lasers-and-Electro-Optics-Society, pp. 330-331.
  • Sweeney SJ, Higashi T, Adams AR, Uchida T, Fujii T. (2000) 'A comparison of AlGaInAs and InGaAsP-based 1.3 mu m semiconductor lasers using high pressure'. GORDON BREACH SCI PUBL LTD HIGH PRESSURE RESEARCH, UNIV MONTPELLIER, MONTPELLIER, FRANCE: XXXVIIth Meeting of the European-High-Pressure-Research-Group (EHPRG) 18 (1-6), pp. 49-55.
  • Phillips AF, Sweeney SJ, Adams AR, Thijs PJA. (1999) 'The hydrostatic pressure dependence of the threshold current in 1.3 mu m InGaAsP quantum well semiconductor diode lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, THESSALONIKI, GREECE: 8th International Conference on High Pressure Semiconductor Physics (HPSP-VIII) 211 (1), pp. 513-518.
  • Sweeney SJ, Adams AR, Silver M, O'Reilly EP, Watling JR, Walker AB, Thijs PJA. (1999) 'Dependence of threshold current on QW position and on pressure in 1.5 mu m InGaAs(P) lasers'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, THESSALONIKI, GREECE: 8th International Conference on High Pressure Semiconductor Physics (HPSP-VIII) 211 (1), pp. 525-531.
  • Adams AR, Silver M, OReilly EP, Gonul B, Phillips AF, Sweeney SJ, Thijs PJA. (1996) 'Hydrostatic pressure dependence of the threshold current in 1.5 mu m strained quantum well lasers'. AKADEMIE VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC RESEARCH, SCHWABISCH GMUND, GERMANY: 7th International Conference on High Pressure Semiconductor Physics (HPSP-VII) 198 (1), pp. 381-388.

Patents

  • Sweeney S. (2009) Optoelectronic Devices. Article number GB0911134.5

Teaching

Current:

Level 2 Solid State Physics

Level 2 Laboratories (2SS/TP)
Level D LabView

Past:

Level 0 Foundation Year Tutorials
Level 1 Principles of Physics (1PP)

Level 1 Electronics (1EL)

Level 1 Physics Laboratories (1LAB)
Level 3 Physics in Education (3PIE) [assessor]
Level M Photonics and Nanotechnology (3PNT)

Departmental Duties

  • Head of Photonics group (2010-)
  • Departmental Management group (2010-)
  • Departmental Policy & Strategy group (2008-)
  • Departmental & Faculty Research Committee (2010-)
  • Chair, Physics Publicity & Marketing group (2010-)
  • Chair of Physics Department Board of Studies (2008-10)
  • Chair of Physics Department BoS sub-committee (2008-10)
  • MPhys/BSc Physics Programme Coordinator (2008-10)
  • Physics with Foundation Year Co-ordinator (2003-2006)
  • Physics Schools Liaison Officer (2004-2008)
  • Physics Marketing group (2006-2008)
  • Physics MPhys research placements co-ordinator (2006-2010)
  • ATI Postgraduate Admissions Tutor (2002-2008)
  • FEPS PG Research committee (2002-2008)

Research Grants

Stephen currently has ~£3M of research funding from sources including EPSRC, EU, TSB and commercial organisations.

Books

  1. "Optoelectronic Devices and Materials", S. J. Sweeney and A. R. Adams, Chapter in Handbook of Electronic Materials, Springer-Verlag, 2006.
  2. "Band-structure and high pressure measurements", B. N. Murdin, A. R. Adams and S. J. Sweeney, in Mid-IR Materials and Devices, Springer, 2006.

Page Owner: phs1ss
Page Created: Monday 10 August 2009 13:24:44 by lb0014
Last Modified: Thursday 17 November 2011 13:51:32 by lb0014
Expiry Date: Wednesday 10 November 2010 13:23:47
Assembly date: Wed Apr 16 22:15:04 BST 2014
Content ID: 11724
Revision: 13
Community: 1256