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Dr Neil Emerson


Associate Tutor

Academic and research departments

Department of Electrical and Electronic Engineering.

My publications

Publications

Reed GT, Thomson D, Gardes FY, Emerson NG, Fedeli J-M (2011) High Speed Silicon optical modulators,OPTOELECTRONIC MATERIALS AND DEVICES VI8308ARTN 83081 SPIE-INT SOC OPTICAL ENGINEERING
In this paper we describe two silicon based optical modulators that have been fabricated as part of two projects in which the Surrey group is involved, the "UK Silicon Photonics project" funded by the UK Engineering and Physical Sciences Research Council (EPSRC), and the European "HELIOS" project funded by the European Union. The modulators exploit the carrier depletion effect in MZI structures, but have different advantages and disadvantages. One has a performance that is close to polarisation independence, whilst the other demonstrates a very high extinction ratio for a 40Gb/s silicon modulator. Both are shown to operate at 40Gb/s. © 2011 SPIE-OSA-IEEE.
Alzanki T, Gwilliam R, Emerson NG, Sealy BJ (2004) Low-temperature processing of antimony-implanted silicon, JOURNAL OF ELECTRONIC MATERIALS33(7)pp. 767-769 MINERALS METALS MATERIALS SOC
Reed GT, Timotijevic BD, Gardes FY, Mashanovich GZ, Headley WR, Emerson NG (2007) Waveguides and devices in Silicon Photonics: Polarisation independence, OPTOELECTRONIC INTEGRATED CIRCUITS IX6476 SPIE-INT SOC OPTICAL ENGINEERING
Emerson NG, Gwilliam RM, Shannon JM, Jeynes C, Sealy BJ, Tsvetkova T, Tzenov N, Tzolov M, Dimova-Malinovska D (2000) Electrical and optical properties of Co+ ion implanted a-Si1-xCx : H alloys, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS160(4)pp. 505-509 ELSEVIER SCIENCE BV
Reed GT, Timotijevic BD, Gardes FY, Mashanovich GZ, Headley WR, Emerson NG (2007) Waveguides and devices in silicon photonics: Polarisation independence, Proceedings of SPIE - The International Society for Optical Engineering6476
Silicon Photonics is experiencing a significant increase in interest due to emerging applications and several high profile successes in device and technology development. One of the most prominent trends in silicon photonics recently has been a trend towards miniaturising waveguides. The shrinking of the device dimensions provides advantages in terms of cost and packing density, modulation bandwidth, improved performance in resonant structures, and an increase in optical power density within the devices. In this paper we analyse several silicon photonics devices based on both small rib and strip waveguides. We have previously reported on issues related to single mode propagation and polarisation independence of silicon waveguides, and produced design rules for such small waveguides that are reviewed here. We have previously reported a modulator based on a small rib waveguide with the height of < 500nm for high speed operation. However, in this paper we consider slightly larger designs to accommodate polarisation independence. Finally we discuss the characteristics of ring and racetrack resonators based on both rib and strip waveguides and methods of improving free spectral range whilst considering polarization effects, and the difficulty in coupling to such strip waveguide based devices. Both theoretical and experimental results are presented. The maximum free spectral range that we have demonstrated experimentally is <43nm.
Mills CA, Sam FLM, Alshammari AS, Rozanski LJ, Emerson NG, Silva SRP (2013) Storage Lifetime of Polymer-Carbon Nanotube Inks for Use as Charge Transport Layers in Organic Light Emitting Diodes,IEEE/OSA Journal of display technology10(2)pp. 125-131 IEEE
The long-term stability of multi-wall carbon nanotubes (MWCNT) mixed with the hole-transport polymer Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been examined. These surfactant stabilised solutions, used as transport layers in organic light emitting diodes (OLEDs), are shown to be stable for periods of up to fifteen months, and show no signs of degrading soon after this time. In comparison, non-stabilised aqueous MWCNT solutions have been shown to aggregate within 30 minutes of production, and, although these aggregates can be re-dispersed, the solution displays an increase in smaller aggregates over time which cannot subsequently be re-dispersed by manual agitation. The stable MWCNT/PEDOT:PSS solutions have been used in ink-jet printing and as composite MWCNT/PEDOT:PSS films suitable as charge transport layers in spin coated organic light emitting diodes.
Alenezi M, Henley S, Emerson N, Silva S (2013) From 1D and 2D ZnO nanostructures to 3D hierarchical structures with enhanced gas sensing properties.,Nanoscale6(1)pp. 235-247
Facile and low cost hydrothermal routes are developed to fabricate three-dimensional (3D) hierarchical ZnO structures with high surface-to-volume ratios and an increased fraction of (0001) polar surfaces. Hierarchical ZnO nanowires (ZNWs) and nanodisks (ZNDs) assembled from initial ZnO nanostructures are prepared from sequential nucleation and growth following a hydrothermal process. These hierarchical ZnO structures display an enhancement of gas sensing performance and exhibit significantly improved sensitivity and fast response to acetone in comparison to other mono-morphological ZnO, such as nanoparticles, NWs, or NDs. In addition to the high surface-to-volume ratio due to its small size, the nanowire building blocks show the enhanced gas sensing properties mainly ascribed to the increased proportion of exposed active (0001) planes, and the formation of many nanojunctions at the interface between the initial ZnO nanostructure and secondary NWs. This work provides the route for structure induced enhancement of gas sensing performance by designing a desirable nanostructure, which could also be extended to synthesize other metal oxide nanostructures with superior gas sensing performance.
Reed GT, Thomson D, Gardes FY, Emerson NG, Fédéli J-M (2011) 40 Gb/s Silicon optical modulators,IEEE Photonic Society 24th Annual Meeting, PHO 2011pp. 737-738 IEEE
In this work we describe two 40Gb/s modulators that have been developed as part of the "UK Silicon Photonics project", and the European "HELIOS" project. The modulators exploit the carrier depletion effect in MZI configurations. © 2011 IEEE.
EMERSON NG, SEALY BJ (1979) EFFECTS OF LASER IRRADIATION OF GAAS OBSERVED BY DLTS, ELECTRONICS LETTERS15(18)pp. 553-554 IEE-INST ELEC ENG
EMERSON NG, SEALY BJ (1980) LASER ANNEALING OF LOW-DOSE SE-IMPLANTED GAAS STUDIED BY DLTS, ELECTRONICS LETTERS16(13)pp. 512-514 IEE-INST ELEC ENG
Reed GT, Mashanovich GZ, Headley WR, Timotijevic B, Gardes FY, Chan SP, Waugh P, Emerson NG, Png CE, Paniccia MJ, Liu A, Hak D, Passaro VMN (2006) Issues associated with polarization independence in silicon photonics,IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS12(6)pp. 1335-1344 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Sealy BJ, Smith AJ, Alzanki T, Bennett N, Li L, Jeynes C, Colombeau B, Collart EJH, Emerson NG, Gwilliam RM, Cowern NEB (2006) Shallow junctions in silicon via low thermal budget processing, Extended Abstracts of the Sixth International Workshop on Junction Technology, IWJT '06pp. 10-15
The paper summarises recent findings concerning the fabrication of ultra-shallow junctions in silicon for future generations of CMOS devices. In particular we concentrate on vacancy engineering to achieve carrier concentrations of 5-6 × 1020 cm-3 for boron in silicon without diffusion and report for the first time preliminary data for antimony implants into strained silicon in which even higher carrier concentrations were obtained. All of this can be produced at temperatures below 800°C for annealing times of 10 seconds, without the need for spike annealing, fast ramp rates or laser processing. © 2006 IEEE.
Gardes FY, Thomson DJ, Emerson NG, Reed GT (2011) 40 Gb/s silicon photonics modulator for TE and TM polarisations,Optics Express19(12)pp. 11804-11814 Optical Society of America
A key device in future high speed short reach interconnect technology will be the optical modulator. These devices, in silicon, have experienced dramatic improvements over the last 6 years and the modulation bandwidth has increased from a few tens of MHz to over 30 GHz. However, the demands of optical interconnects are significant. Here we describe an approach based on a self-aligned wrap around p-n junction structure embedded in a silicon waveguide that can produce high-speed optical phase modulation, whilst at the same time, capable of a high extinction ratio. An all-silicon optical modulator using a CMOS compatible fabrication process with a data rate of 40 Gb/s and extinction ratio up to approximately 6.5 dB for TE and TM polarisations is demonstrated. This technology is not only compatible with conventional complementary MOS (CMOS) processing, but is also intended to simplify and improve the reliability of, the fabrication process.
Milosevic MM, Nedeljkovic M, Ben Masaud TM, Jaberansary E, Chong HMH, Emerson NG, Reed GT, Mashanovich GZ (2012) Silicon waveguides and devices for the mid-infrared, Applied Physics Letters101(12)121105 American Institute of Physics
We report on the design, fabrication, and characterization of silicon-on-insulator rib and strip waveguides at wavelengths longer than 3.7 µm. Propagation losses of 1.5±0.2 dB/cm at 3.73 µm and 1.8±0.2 dB/cm at 3.8 µm have been measured for rib waveguides, whilst submicron strip waveguides exhibited propagation losses of 4.6±1.1 dB/cm at the wavelength of 3.74 µm. A 1×2 multimode interference (MMI) splitter and racetrack resonators based on submicron strip waveguides are also examined. Optical losses of 3.6±0.2 dB/MMI and a racetrack resonator Q-value of 8.2 k are obtained at 3.74 µm.
Gwilliam RM, Hutchinson S, Shannon JM, Emerson NG, Sealy BJ (1998) Low resistivity layers and Schottky contacts in amorphous silicon by Co+ implantation, ELECTRONICS LETTERS34(25)pp. 2441-2442 IEE-INST ELEC ENG
Reed GT, Thomson D, Gardes FY, Emerson NG, Fédéli J-M (2011) High Speed Silicon optical modulators,2011 Asia Communications and Photonics Conference and Exhibition, ACP 2011
In this paper we describe two silicon based optical modulators that have been fabricated as part of two projects in which the Surrey group is involved, the "UK Silicon Photonics project" funded by the UK Engineering and Physical Sciences Research Council (EPSRC), and the European "HELIOS" project funded by the European Union. The modulators exploit the carrier depletion effect in MZI structures, but have different advantages and disadvantages. One has a performance that is close to polarisation independence, whilst the other demonstrates a very high extinction ratio for a 40Gb/s silicon modulator. Both are shown to operate at 40Gb/s. © 2011 SPIE-OSA-IEEE.
Gardes FY, Reed GT, Emerson NG, Png CE (2005) A sub-micron depletion-type photonic modulator in Silicon On Insulator, OPTICS EXPRESS13(22)pp. 8845-8854 OPTICAL SOC AMER
Miloaevi? MM, Emerson NG, Gardes FY, Chen X, Adikaari AA, Mashanovich GZ (2011) Athermal waveguides for optical communication wavelengths., Opt Lett36(23)pp. 4659-4661
We report on the design, fabrication, and characterization of temperature insensitive strip silicon-on-insulator racetrack resonators. The influence of various parameters, such as waveguide width, waveguide height, ring radius, coupling length, ring gap, and operating wavelength, on temperature-dependent wavelength shift is examined. A resonant wavelength shift of 0.2 pm/K at a 1550 nm wavelength is measured for 335 nm×220 nm waveguides. A significant reduction of waveguide propagation losses, improved ring Q value, and higher extinction ratio are obtained after overlaying the silicon waveguides with a polymer cladding.
Emerson NG, Gwilliam RM, Sealy BJ (2001) Ion beam synthesis of low resistivity contacts in amorphous silicon-based materials, JOURNAL OF ELECTRONIC MATERIALS30(2)pp. L5-L7 MINERALS METALS MATERIALS SOC