Dr Vlad Stolojan
Lecturer
Qualifications: BSc, PhD cantab, AMInstP
Email: v.stolojan@surrey.ac.uk
Phone: Work: 01483 68 9411
Room no: 25 ATI 02
Further information
Biography
Dr Vlad Stolojan is a Lecturer in Nanomaterials Characterisation, working in the Advanced Technology Institute as part of the Nano-Electronics Centre. He is a member of the Institute of Physics and a fellow of the Royal Microscopical Society.
Dr Stolojan is an alumni of University of East Anglia (BSc Physics -1996) and of the University of Cambridge (PhD Physics -2001 – “Nanochemistry of grain boundaries in iron). He first joined the University of Surrey’s School of Engineering in 2001 as an expert electron microscopy and energy-loss spectroscopy, continuing as an RCUK Fellow with the University of Surrey’s Electronic Engineering department, in Prof Ravi Silva’s group.
Dr Stolojan is an author of over 80 peer-reviewed publications, a reviewer for a number of journals (Carbon, Applied Surface Science, Ultramicroscopy, etc.) and a member of the Materials Engineering and Nanotechnology Panel of the National Council for Certification of University Degrees, Romania (CNATDCU).
Research Interests
- Electron Microscopy and associated spectroscopy, particularly Electron Energy-Loss Spectroscopy;
- Mechanisms and models for the catalytic growth of carbon nanotubes and graphene;
- Focussed Ion Beam Microscopy, Fabrication and manipulation;
- Optical microlenses and concentrators;
- Photovoltaic devices.
Publications
Highlights
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(2011) 'Growth of carbon nanotubes at temperatures compatible with integrated circuit technologies'. PERGAMON-ELSEVIER SCIENCE LTD CARBON, 49 (1), pp. 280-285.Full text is available at: http://epubs.surrey.ac.uk/735951/
- . (2010) 'Top-Down Heating for Low Substrate Temperature Synthesis of Carbon Nanotubes'. AMER SCIENTIFIC PUBLISHERS JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 10 (6), pp. 3952-3958.
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(2009) 'Pulsed laser deposited tetrahedral amorphous carbon with high sp(3) fractions and low optical bandgaps'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 105 (7) Article number ARTN 073521 doi: 10.1063/1.3095667Full text is available at: http://epubs.surrey.ac.uk/733930/
- . (2008) 'The inner shell influence on the electronic structure of double-walled carbon nanotubes'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 20 (1), pp. 189-+.
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(2007) 'Inner-tube chirality determination for double-walled carbon nanotubes by scanning tunneling microscopy'. AMER CHEMICAL SOC NANO LETTERS, 7 (5), pp. 1232-1239.doi: 10.1021/nl070072p
Journal articles
- . (2013) 'Chemico-physical characterisation and in vivo biocompatibility assessment of DLC-coated coronary stents'. SPRINGER HEIDELBERG ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 405 (1), pp. 321-329.
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(2012) 'Laser implantation of plasmonic nanostructures into glass.'. Nanoscale, doi: 10.1039/c2nr33629d
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(2012) 'Hybrid carbon nanotube networks as efficient hole extraction layers for organic photovoltaics'. ACS Nano, 7 (1), pp. 556-565.doi: 10.1021/nn304705t
- . (2012) 'Characterisation of gold nanoparticles and rods using high angle annular dark field imaging'. Journal of Nanoparticle Research, 14 (4)
- . (2012) 'Catalysing the production of multiple arm carbon octopi nanostructures'. Carbon, 50 (6), pp. 2141-2146.
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(2012) 'Photo-thermal chemical vapor deposition growth of graphene'. Elsevier Carbon, 50 (2), pp. 668-673.Full text is available at: http://epubs.surrey.ac.uk/22849/
Abstract
The growth of graphene on Ni using a photo-thermal chemical vapor deposition (PT-CVD) technique is reported. The non-thermal equilibrium nature of PT-CVD process resulted in a much shorter duration in both heating up and cooling down stages, thus allowing for a reduction in the overall growth time. Despite the reduced time for synthesis compared to standard thermal chemical vapor deposition (T-CVD), there was no decrease in the quality of the graphene film produced. Furthermore, the graphene formation under PT-CVD is much less sensitive to cooling rate than that observed for T-CVD process. Growth on Ni also allows for the alleviation of hydrogen blister damage that is commonly encountered during growth on Cu substrates and a lower processing temperature. To characterize the film’s electrical and optical properties, we further report the use of pristine PT-CVD grown graphene as the transparent electrode material in an organic photovoltaic device (OPV) with poly(3-hexyl)thiophene (P3HT)/phenyl-C61-butyric acid methyl ester (PCBM) as the active layer where the power conversion efficiency of the OPV cell is found to be comparable to that reported using pristine graphene prepared by conventional CVD.
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(2011) 'Probing the band structure of hydrogen-free amorphous carbon and the effect of nitrogen incorporation'. CARBON, 49 (15), pp. 5229-5238.Full text is available at: http://epubs.surrey.ac.uk/7817/
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(2011) 'Raman analysis of oxide cladded silicon core nanowires grown with solid silicon feed stock'. SPRINGER JOURNAL OF NANOPARTICLE RESEARCH, 13 (7), pp. 2697-2703.Full text is available at: http://epubs.surrey.ac.uk/7830/
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(2011) 'Spontaneous emergence of long-range shape symmetry'. Nano Letters, United States: 11 (1), pp. 160-163.doi: 10.1021/nl1032793
- . (2011) 'Synthesis of linear ZnO structures by a thermal decomposition method and their characterisation'. Springer Journal of Materials Science, 47 (4), pp. 1893-1901.
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(2011) 'Growth of carbon nanotubes at temperatures compatible with integrated circuit technologies'. PERGAMON-ELSEVIER SCIENCE LTD CARBON, 49 (1), pp. 280-285.Full text is available at: http://epubs.surrey.ac.uk/735951/
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(2010) 'High-rate low-temperature growth of vertically aligned carbon nanotubes'. IOP PUBLISHING LTD NANOTECHNOLOGY, 21 (50) Article number ARTN 505604 Full text is available at: http://epubs.surrey.ac.uk/7831/
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(2010) 'Growth and characterization of ceria thin films and Ce-doped gamma-Al2O3 nanowires using sol-gel techniques'. IOP PUBLISHING LTD NANOTECHNOLOGY, 21 (46) Article number ARTN 465606 Full text is available at: http://epubs.surrey.ac.uk/7517/
- . (2010) 'The growth of silica and silica-clad nanowires using a solid-state reaction mechanism on Ti, Ni and SiO2 layers'. IOP PUBLISHING LTD NANOTECHNOLOGY, 21 (29) Article number ARTN 295603
- . (2010) 'Top-Down Heating for Low Substrate Temperature Synthesis of Carbon Nanotubes'. AMER SCIENTIFIC PUBLISHERS JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 10 (6), pp. 3952-3958.
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(2010) 'The effect of silane incorporation on a metal adhesive interface: A study by electron energy loss spectroscopy'. PERGAMON-ELSEVIER SCIENCE LTD MICRON, 41 (2), pp. 130-134.Full text is available at: http://epubs.surrey.ac.uk/712195/
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(2009) 'Enhancement of phosphorus activation in vacancy engineered thin silicon-on-insulator substrates'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 106 (10) Article number ARTN 103514 doi: 10.1063/1.3262527Full text is available at: http://epubs.surrey.ac.uk/745813/
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(2009) 'From Stems (and Stars) to Roses: Shape-Controlled Synthesis of Zinc Oxide Crystals'. AMER CHEMICAL SOC CRYSTAL GROWTH & DESIGN, 9 (8), pp. 3432-3437.doi: 10.1021/cg8013333Full text is available at: http://epubs.surrey.ac.uk/734224/
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(2009) 'Pulsed laser deposited tetrahedral amorphous carbon with high sp(3) fractions and low optical bandgaps'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 105 (7) Article number ARTN 073521 doi: 10.1063/1.3095667Full text is available at: http://epubs.surrey.ac.uk/733930/
- . (2008) 'The role of the gas species on the formation of carbon nanotubes during thermal chemical vapour deposition'. IOP PUBLISHING LTD NANOTECHNOLOGY, 19 (44) Article number ARTN 445605
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(2008) 'Reversible increase of photocurrents in excimer laser-crystallized silicon solar cells'. Solar Energy Materials and Solar Cells, 92 (11), pp. 1378-1381.Full text is available at: http://epubs.surrey.ac.uk/745814/
Abstract
Excimer laser-crystallized silicon solar cells fabricated show a steady increment of the current densities with exposure to simulated sunlight, over a 30 min period. The current density of the amorphous silicon cell under identical conditions remains steady, with no significant change. The process was observed to be reversible upon cooling, and the performance increase is attributed to the energy barrier introduced by the enhanced bandgap of a nanocrystalline silicon middle layer, created as a result of the crystallization. It is suggested that the thermal energy due to prolonged illumination allows carriers to cross the barrier increasing output currents. © 2008 Elsevier B.V. All rights reserved.
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(2008) 'A fast sonochemical approach for the synthesis of solution processable ZnO rods'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 104 (7) Article number ARTN 074906 doi: 10.1063/1.2988295Full text is available at: http://epubs.surrey.ac.uk/733931/
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(2008) 'Electronic state modification in laser deposited amorphous carbon films by the inclusion of nitrogen'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 104 (6) Article number ARTN 063701 doi: 10.1063/1.2977718Full text is available at: http://epubs.surrey.ac.uk/733932/
- . (2008) 'Scanning Transmission Electron Microscopy: A Tool for Biology and Materials Science'. John Wiley & sons Microscopy and Analysis, 22 (4), pp. 15-18.
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(2008) 'Failure mechanisms in adhesively bonded aluminium: an XPS and PEELS study'. JOHN WILEY & SONS LTD SURFACE AND INTERFACE ANALYSIS, 40 (3-4), pp. 128-131.doi: 10.1002/sia.2651Full text is available at: http://epubs.surrey.ac.uk/712203/
- . (2008) 'The inner shell influence on the electronic structure of double-walled carbon nanotubes'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 20 (1), pp. 189-+.
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(2008) 'Characterisation of electron-beam deposited tungsten interconnects'. Journal of Physics: Conference Series, 126 (1) Article number 012073 Full text is available at: http://epubs.surrey.ac.uk/732873/
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(2008) 'One-pot rapid low-cost synthesis of Pd-fullerite catalysts'. ROYAL SOC CHEMISTRY JOURNAL OF MATERIALS CHEMISTRY, 18 (40), pp. 4808-4813.doi: 10.1039/b807963c
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(2007) 'Nanostructured copper phthalocyanine-sensitized multiwall carbon nanotube films'. AMER CHEMICAL SOC LANGMUIR, 23 (11), pp. 6424-6430.doi: 10.1021/la070156d
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(2007) 'Inner-tube chirality determination for double-walled carbon nanotubes by scanning tunneling microscopy'. AMER CHEMICAL SOC NANO LETTERS, 7 (5), pp. 1232-1239.doi: 10.1021/nl070072p
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(2007) 'Electron field emission properties of co quantum dots in SiO
matrix synthesised by ion implantation'. IEEE IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium, , pp. 47-48.Full text is available at: http://epubs.surrey.ac.uk/745825/
Abstract
Crystallised Co nanoparticles were synthesized by Co+ implantation onto thermally oxidised SiO2 layers on silicon substrate. The implantation energy was 50 keV and the doses ranged from 1 to 7times1016 Co+/cm2. The possibility of controlling the size and distribution of the nanoclusters by changing implantation conditions (e.g. dose and energy) is the main advantage of this technique. Atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (X-TEM) were used to characterize the nanoclusters. The staircase I-V curve also shows that the metallic quantum dots embedded in a thin SiO2 layer on silicon substrate has effective Coulomb blockade at room temperature
- . (2007) 'Observation of van der Waals driven self-assembly of MoSI nanowires into a low-symmetry structure using aberration-corrected electron microscopy'. WILEY-V C H VERLAG GMBH ADVANCED MATERIALS, 19 (4), pp. 543-+.
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(2006) 'Damage effects in Pyrex by CF4 reactive ion etching in dual RF-microwave plasmas'. INST ENGINEERING TECHNOLOGY-IET MICRO & NANO LETTERS, 1 (2), pp. 103-107.doi: 10.1049/mnl:20065059
- . (2006) 'Bandgap enhancement of layered nanocrystalline silicon from excimer laser crystallization'. IOP PUBLISHING LTD NANOTECHNOLOGY, 17 (21), pp. 5412-5416.
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(2006) 'Negative differential conductance observed in electron field emission from band gap modulated amorphous-carbon nanolayers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (19) Article number ARTN 193103 doi: 10.1063/1.2378492Full text is available at: http://epubs.surrey.ac.uk/733934/
- . (2006) 'Microstructure analyses of metal-filled carbon nanotubes synthesized by microwave plasma-enhanced chemical vapor deposition'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE TRANSACTIONS ON NANOTECHNOLOGY, 5 (5), pp. 485-490.
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(2006) 'Controlled growth-reversal of catalytic carbon nanotubes under electron-beam irradiation.'. Nano Lett, United States: 6 (9), pp. 1837-1841.doi: 10.1021/nl060709p
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(2006) 'Structural and optoelectronic properties of C-60 rods obtained via a rapid synthesis route'. ROYAL SOC CHEMISTRY JOURNAL OF MATERIALS CHEMISTRY, 16 (37), pp. 3715-3720.doi: 10.1039/b609074e
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(2006) 'Subnanometer-resolved measurement of the tunneling effective mass using bulk plasmons'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 88 (12) Article number ARTN 122109 doi: 10.1063/1.2188593Full text is available at: http://epubs.surrey.ac.uk/745826/
Abstract
Superlattices are periodic structures where the constituents alternate between low- and high-bandgap materials; the resulting quantum confinement tailors the resulting device properties and increases their operating speed. Amorphous carbon is an excellent candidate for both the well and barrier layers of the superlattices, leading to a fast and reliable device manufacturing process. We show theoretically and experimentally that, using low energy-loss spatially resolved spectroscopy, we can characterize the component layers of a superlattice. We measure quantum confinement of the electron wave function in the superlattice's wells and calculate the effective tunneling mass for amorphous carbon superlattices as m* =0.067 me. This effective mass makes diamondlike carbon films as feasible candidate for electronic devices. © 2006 American Institute of Physics.
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(2006) 'Energy loss spectroscopic profiling across linear interfaces: The example of amorphous carbon superlattices'. ELSEVIER SCIENCE BV ULTRAMICROSCOPY, 106 (4-5), pp. 346-355.Full text is available at: http://epubs.surrey.ac.uk/745822/
Abstract
Energy loss spectroscopic profiling is a way to acquire, in parallel, spectroscopic information across a linear feature of interest, using a Gatan imaging filter (GIF) fitted to a transmission electron microscope (TEM). This technique is capable of translating the high spatial resolution of a bright field image into a sampling of the spectral information with similar resolution. Here we evaluate the contributions of chromatic aberration and the various acquisition parameters to the spatial sampling resolution of the spectral information, and show that this can reach 0.5 nm, in a system not ordinarily capable of forming electron probes smaller than 2 nm. We use this high spatial sampling resolution to study the plasmon energy variation across amorphous carbon superlattices, in order to extract information about their structure and electronic properties. By modelling the interaction of the relativistic incident electrons with a dielectric layer sandwiched between outer layers, we show that, due to the screening of the interfaces and at increased collection angles, the plasmon energy in the sandwiched layer can still be identified for layer thicknesses down to 5 A. This allows us to measure the change in the well bandgap as a function of well width and to interpret it in terms of the changes in the sp2 -fractions due to the deposition method, as measured from the carbon K-edges, and in terms of quantum confinement of the well wavefunction by the adjacent barriers.
- . (2006) 'Negative differential conductance observed in electron field emission from band gap modulated A-C nanolayers'. IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium, , pp. 199-200.
- . (2006) 'Nanomaterials: Nanotube growth surface-driven'. Advanced Composites Bulletin, (NOV.), pp. 3-3.
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(2005) 'Deployment of titanium thermal barrier for low-temperature carbon nanotube growth'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 87 (25) Article number ARTN 253115 doi: 10.1063/1.2150587Full text is available at: http://epubs.surrey.ac.uk/745823/
Abstract
Chemical vapor-synthesized carbon nanotubes are typically grown at temperatures around 600 °C. We report on the deployment of a titanium layer to help elevate the constraints on the substrate temperature during plasma-assisted growth. The growth is possible through the lowering of the hydrocarbon content used in the deposition, with the only source of heat provided by the plasma. The nanotubes synthesized have a small diameter distribution, which deviates from the usual trend that the diameter is determined by the thickness of the catalyst film. Simple thermodynamic simulations also show that the quantity of heat, that can be distributed, is determined by the thickness of the titanium layer. Despite the lower synthesis temperature, it is shown that this technique allows for high growth rates as well as better quality nanotubes. © 2005 American Institute of Physics.
Conference papers
- . (2010) 'Direct catalytic growth of high-density carbon nanotubes on nanoclusters at low temperatures'. Proceedings of 8th International Vacuum Electron Sources Conference and Nanocarbon, Nanjing, China: 8th IVEC 2010, pp. 389-389.
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(2010) 'GeTe-filled carbon nanotubes for data storage applications'. Cambridge University Press MRS Proceedings, California, USA: 2010 MRS Spring Meeting: Symposium H – Phase-Change Materials for Memory and Reconfigurable Electronics Applications 1251, pp. 19-24.Full text is available at: http://epubs.surrey.ac.uk/745831/
Abstract
By virtue of their unique electronic properties, nanometer-diameter sized single-walled carbon nanotubes represent ideal candidates to function as active parts of nanoelectronic memory storage devices. We show for the first time that GeTe, a phase change material, currently considered to be one of the most promising materials for data-storage applications, can efficiently be encapsulated within single-walled carbon nanontubes of 1.4 nm diameter. Structural investigations on the encapsulated GeTe nanowires have been carried out by high resolution transmission electron microscopy. The electronic interactions between the filling material and the host nanotube have been examined using ultraviolet photoelectron spectroscopy experiments and show that the electronic structure of the encapsulating nanotube and that of the encased filling are not perturbed by the presence of each of the other component. The newly formed hybrids offer potential to operate as active elements in non-volatile electronic memory storage devices.
- . (2010) 'Carbon nanotube field effect transistor measurements in vacuum'. IEEE IEEE Proceedings of International Conference on Semiconductor Electronics, Melaka, Malaysia: ICSE 2010, pp. 224-228.
- . (2009) 'High concentration Mn ion implantation in Si'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Dresden, GERMANY: 16th International Conference on Ion Beam Modification of Materials 267 (8-9), pp. 1623-1625.
- . (2008) 'Engineering the shape of zinc oxide crystals via sonochemical or hydrothermal solution-based methods'. Materials Research Society Proceedings, San Francisco, USA: 2008 MRS Spring Meeting Symposium V – Crystal-Shape Control and Shape-Dependent Properties – Methods, Mechanism, Theory and Simulation 1087, pp. 59-65.
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(2008) 'Improving the electron emission properties of ion-beam-synthesized Ag-SiO2 nanocomposites by pulsed laser annealing'. A V S AMER INST PHYSICS JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Chicago, IL: 20th International Vacuum Nanoelectronics Conference 26 (2), pp. 860-863.doi: 10.1116/1.2824970
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(2008) 'In situ Observation of the Growth of Tungsten Oxide Nanostructures'. SPRINGER-VERLAG BERLIN MICROSCOPY OF SEMICONDUCTING MATERIALS 2007, Univ Cambridge, Cambridge, ENGLAND: 15th Conference on Microscopy of Semiconducting Materials 120, pp. 277-280.Full text is available at: http://epubs.surrey.ac.uk/745821/
- . (2008) 'Influences of hydrogen gas on carbon nanotube growth'. Materials Research Society Symposium Proceedings, San Francisco, USA: 2008 MRS Spring Meeting: Symposium P – Carbon Nanotubes and Related Low-Dimensional Materials 1081, pp. 87-93.
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(2008) 'Characterisation of electron-beam deposited tungsten interconnects'. EMAG: ELECTRON MICROSCOPY AND ANALYSIS GROUP CONFERENCE 2007, 126Full text is available at: http://epubs.surrey.ac.uk/732874/
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(2008) 'The Dielectric Properties of Co-Implanted SiO(2) Investigated Using Spatially-Resolved EELS'. SPRINGER-VERLAG BERLIN MICROSCOPY OF SEMICONDUCTING MATERIALS 2007, Univ Cambridge, Cambridge, ENGLAND: 15th Conference on Microscopy of Semiconducting Materials 120, pp. 341-344.Full text is available at: http://epubs.surrey.ac.uk/745834/
- . (2008) 'Gas Sensing Properties of Vapour-Deposited Tungsten Oxide Nanostructures'. SPRINGER-VERLAG BERLIN MICROSCOPY OF SEMICONDUCTING MATERIALS 2007, Univ Cambridge, Cambridge, ENGLAND: 15th Conference on Microscopy of Semiconducting Materials 120, pp. 281-284.
- . (2007) 'Electrical conduction mechanism in laser deposited amorphous carbon'. ELSEVIER SCIENCE SA THIN SOLID FILMS, San Diego, CA: 34th International Conference on Metallurgical Coatings and Thin Films 516 (2-4), pp. 257-261.
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(2007) 'The structural and electron field emission properties of ion-beam-synthesised metallic-dielectric nanocomposites'. INST PROBLEMS MECHANICAL ENGINEERING-RUSSIAN ACAD SCIENCES REVIEWS ON ADVANCED MATERIALS SCIENCE, Warsaw Univ Technol, Warsaw, POLAND: Fall Meeting of the European-Materials-Research-Society 15 (3), pp. 179-184.Full text is available at: http://epubs.surrey.ac.uk/745835/
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(2007) 'Electron field emission properties of Co quantum dots in SiO2 matrix synthesised by ion implantation'. ELSEVIER SCIENCE BV ULTRAMICROSCOPY, Guilin, PEOPLES R CHINA: Joint 50th International Field Emission Symposium/19th International Vacuum Nanoelectronics Conference 107 (9), pp. 819-824.Full text is available at: http://epubs.surrey.ac.uk/745836/
Abstract
In this work, Co ions were implanted into thermally oxidised SiO2 layers on silicon substrates. The implantation energy was 50 keV and the doses were 1, 3, 5 and 7 x 10(16) Co+/cm2. The field emission (FE) properties of these layers were studied and correlated with results from atomic force microscopy and transmission electron microscopy measurements. Other than that for the lowest dose sample, crystallised Co nanoclusters, with sizes ranging from 1.8 to 5.7 nm, are observed in these Co-implanted layers. The higher dose samples exhibit excellent FE properties and give an emission current of 1 nA at electric fields as low as 5 V/microm, for a dose of 5 x 10(16) Co+/cm2, compared with 120 V/microm for the lowest dose samples. We attribute the excellent FE properties of these layers to the formation of Co nanoclusters, with the electrical inhomogeneity giving rise to local field enhancement. Finally, repeatable staircase-like current-field (I-F) characteristics are observed in FE measurements of these higher dose samples as compared to conventional Fowler-Nordheim-type I-F characteristics in the lower dose sample. We believe this data may be a result of Coulomb blockade effects arising from the isolated low-capacitance metal quantum dots formed by controlled ion implantation.
- . (2007) 'Improving the electron emission properties of ion-beam-synthesized Ag-SiO nanocomposites by pulsed laser annealing'. Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07, , pp. 102-103.
- . (2007) 'Manufacture of carbon multi-walled nanotubes by the arc discharge technique'. INT ASSOC ENGINEERS-IAENG World Congress on Engineering 2007, Vols 1 and 2, London, ENGLAND: World Congress on Engineering 2007, pp. 1391-1395.
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(2006) 'Nanostructural studies of PVD TiAlB coatings'. JOHN WILEY & SONS LTD SURFACE AND INTERFACE ANALYSIS, Vienna, AUSTRIA: 11th European Conference on Applications of Surface and Interface Anlaysis 38 (4), pp. 731-735.doi: 10.1002/sia.2160
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(2006) 'Electron field-emission properties of Ag-SiO2 nanocomposite layers'. A V S AMER INST PHYSICS JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Oxford, ENGLAND: 18th International Vacuum Nanoelectronics Conference 24 (2), pp. 958-961.doi: 10.1116/1.2165669Full text is available at: http://epubs.surrey.ac.uk/745829/
Abstract
In this work, Ag-Si O2 nanocomposite layers were synthesized by introducing Ag nanoclusters into thermally oxidized Si O2 layers, using ion implantation. The field-emission (FE) properties of these layers were studied and correlated with the results from atomic force microscopy and transmission electron microscopy measurements. These nanocomposites exhibit good FE properties and give an emission current of 1 nA at electric fields as low as 13 Vμm, for a dose of 5× 1016 Ag+ cm2, compared with 204 Vμm for "bare" Si O2 layers. It is clearly demonstrated that the good FE properties of these nanocomposites are attributed to two types of local-field enhancement: one due to the surface morphology and the other due to electrical inhomogeneity. The isolated conductive Ag nanoclusters embedded in the electrically insulating Si O2 matrix provide a field enhancement due to the electrical inhomogeneity effect. Moreover, the implanted Ag ions diffuse to the surface, during the implantation process, and create dense surface-protrusion structure which provides a geometric local-field enhancement. The local-field-enhancement mechanisms in these samples are critically dependent on the implantation dose of Ag. © 2006 American Vacuum Society.
- . (2006) 'Novel approach to low substrate temperature synthesis of carbon nanotubes'. IEEE 2006 IEEE Conference on Emerging Technologies - Nanoelectronics, Singapore, SINGAPORE: IEEE Conference on Emerging Technologies - Nanoelectronics, pp. 254-257.
- . (2006) 'Microstructure analyses of metal-filled carbon nanotubes synthesized by microwave plasma-enhanced chemical vapour deposition'. IEEE 2006 IEEE Conference on Emerging Technologies - Nanoelectronics, Singapore, SINGAPORE: IEEE Conference on Emerging Technologies - Nanoelectronics, pp. 93-98.
- . (2006) 'Growth of tungsten oxide nanowires using simple thermal heating'. IEEE 2006 IEEE Conference on Emerging Technologies - Nanoelectronics, Singapore, SINGAPORE: IEEE Conference on Emerging Technologies - Nanoelectronics, pp. 376-378.
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(2005) 'Quantum effects in band gap-modulated amorphous carbon superlattices'. SPRINGER-VERLAG BERLIN Microscopy of Semiconducting Materials, Univ Oxford, Oxford, ENGLAND: 14th Conference on Microscopy of Semiconducting Materials 107, pp. 307-310.Full text is available at: http://epubs.surrey.ac.uk/745824/
Teaching
- EEEM037 –Advanced Experimental Methods (Module Co-ordinator): This module covers data processing and analysis, microscopy image processing and analysis, optical spectroscopies, carbon nanotube growth mechanisms, thin film deposition techniques, ion-beam fabrication, implantation and analysis and journal article writing.
- EEE3025 – Introduction to Nanotechnology (with Dr JD Carey): Dr Stolojan’s component covers the use of electron and ion microscopy and spectroscopy in nanotechnology.
- Dr Stolojan is an academic supervisor for Multi-Disciplinary Design Projects, a tutor on Level 1 Maths and contributes to the Engineering Design and Professional Skills.
Departmental Duties
- ATI Outreach Officer and Schools Liaison.
- Academic in charge of the Transmission Electron Microscopes (STEM, TEM) in Materials Structural Studies Unit (MSSU), and the microscopy and analysis suite at the ATI: SEM, ESEM, Dual-Beam FIB, AFM, Scanning Tunneling Microscope (STM) with XPS, UPS and an SEM column.
Affiliations
Institute of Physics (EMAG and The arbon Group): AMInstP.
Fellow of the Royal Microscopical Society.
