Advanced Materials Research Laboratory (A.M.R.L.)
Dr. Andy Wright
Current research opportunities in AMRL
The Advanced Materials Research Laboratory (AMRL) was established in 1992 as a center for both fundamental and applied research in novel materials at Glyndŵr University in Wrexham. Previous research activities had concentrated on the growth of both conventional (ZnSe, ZnS) and novel (Ga2Se3, CdMgS) wide band-gap compound semiconductor materials as thin films using the technique of metal-organic chemical vapour deposition (MOCVD) for blue-green optoelectronics.
Currently, a major focus of activity in the group is the broad but rapidly expanding area of Nanotechnology with particular emphasis on nanowires including carbon nanotubes. We invented a technique for the direct patterning of vertically aligned metal nanowires using concentrated, focussed magnetic fields and realised a simple field emission device in this way. We also developed a technique (with Leicester University, Prof Andrew Abbott) for conformal overplating of carbon nanotubes with chromium metal using novel ionic liquids and discovered that when formed at low coverage’s that the metal clusters are magnetic. We have also recently discovered that mouse muscle precursor cells are highly aligned on the exposed edges of single walled carbon nanotubes (paper submitted to J. Materials Science and Engineering C). This work is a collaboration with Keele University (Dr. Ian Holt).
We have also just started (1st November 2012) a project funded by STFC to develop a more efficient polymer solar cell. This is in collaboration with Rutherford Appleton Laboratories, Oxfordshire.
The laboratory also engages with local industry to help develop products and processes. In 2004 the laboratory completed a Knowledge Transfer Partnership (KTP) project (KTP-online) with Micro Materials Ltd (Wrexham) to develop both high temperature and cold stages for their NanoTest instrument. In 2012 we completed another KTP with Ellison Sensors International Ltd to bring in-house the processes for production of silicon-on-sapphire based pressure sensors.
- EPSRC previously funded (March 2000) a project (GR/N11186) to undertake a fundamental study of the growth of carbon nanotubes by CVD. The project is based around our unique joint CVD-to-STM system as described here The project also used high resolution TEM and micro-RAMAN (with Prof.Young, Manchester Materials Centre) to gain a far better understanding of how carbon nanotubes grow from nano-sized transition metal clusters (Fe, Ni, Co or Mo) deposited onto planar substrates. The results of the initial study can be found in our publications section. Current activity has now moved from research into a proof-of-concept stage under the WDA Knowledge Exploutation Fund (KEF) programme. See the Nanotube site to get a broader overview of this area of research.
- Chemical Vapour Deposition (CVD) is widely used to synthesise thin solid films of advanced materials but is not well understood at the fundamental level. The chemistry is complex as both gas-phase and surface driven reactions can occur simultaneously. The high ambient gas pressure precludes the use of electron spectroscopies for performing experimental studies and although optical probes such as RAS (Reflectance Anisotropy Spectroscopy) can monitor the surface in real time, the only way to understand CVD on a molecular level is through high level modelling and simulation. First-principles (ab-initio) techniques have been used such as Gaussian together with Monte-Carlo modelling to perform studies of the growth processes of compound semiconductors.
- EPSRC previously funded, under its Electronic Materials for Displays (EMD) Initiative, a project (GR/N28009) to develop Gallium Nitride (GaN) as a powder phosphor for Electroluminescent (EL) flexible flat-panel displays. This material is expected to yield far longer device lifetimes than the currently used ZnS phosphors. Rare-earth doping will be used to gain superior colour purity over the use of alloys.
Collaborations with other organisations included Manchester University (TEM studies of rare-earths in both GaAs and Si/SiGe Dept. EE&E), microwave ceramics (Materials Science Centre), High Modulus PBO fibres (Materials Science Centre) and with Coventry University the study of ACEL ZnS:Cu,Cl powder phosphors (Centre for Data Storage Materials). We also had a collaboration with the European Space Agency (Noordwijk) on the development of superconductive tunnelling junction photon detectors for astronomy (S-CAM project) where structural diagnostics were provided by us using TEM.
In addition to the STM-CVD system , the facility consists of three laboratories for wafer preparation, thin film growth.
- Dedicated carbon nanotube thin film growth system. Two reactors, one for SWNT and one for PACVD.
- Vacuum coating via an Edwards E306 evaporator enables metallisation for simple devices
- Sputter coating up to 2” wafers with heated wafer stage.
- Optical microscopy consists of a Reicher Polyvar Met fitted with a Normarski attachment, Olympus Vanox-T for transmission with polarised light, Olympus Stereozoom, Leitz 20EB with fluorescence and phase contrast.
- More recent additions to the equipment base have included a Avantes spectrometer for absolute irradiance measurements in the visible spectrum fibre-optically coupled to a monochromated high pressure mercury lamp for UV excitation
- Controlled atmosphere tube furnace (1200 °C max) with a silica glass flow tube capable of nitridation in high purity ammonia or annealing under high purity hydrogen or nitrogen gases. This system can also be used for wafer oxidation using pure O2 or forming gas (H2/N2 mixtures) for ohmic contact formation.
- Electroplating and anodising at controlled temperature.
- Tissue engineering
Highly aligned Mouse Muscle cells grown on edges of thick Single Walled Carbon Nanotube films
Andrew C. Wright and Ian Holt, J. Materials Science and Engineering C submitted
Magnetophoretic Assembly and printing of nanowires
Andrew C. Wright and Michael Faulkner
J. Vacuum Science and Technology B 30(2) (2012) 021603 See http://epubs.glyndwr.ac.uk/amrl/14/ for download
- Carbon Nanotubes
Nanomagnetic domains of chromium deposited on vertically-aligned carbon nanotubes
Andrew C. Wright, Michael K. Faulkner, Robert C Harris, Alex Goddard and Andrew P. Abbott
J. Magnetism and Magnetic Materials 324(24) (2012) 4170-4174 See http://epubs.glyndwr.ac.uk/amrl/15/ for download
The influence of the substrate on the growth of carbon nanotubes from nickel clusters -an investigation using STM, FE-SEM, TEM and Raman spectroscopy
A C Wright, Y Xiong, N Maung, S J Eichhorn and R J Young
Materials Scince and Engineering C 23 (2003) 279-283 (PDF)
High resolution and conventional transmission electron microscopy of Ga2Se3 thin films grown by vapour phase epitaxy
A C Wright and J O Williams, A Krost, W Richter and D R T Zahn
J. Crystal Growth 121 (1992) No's 1/2 111
Mass-spectrometric study of the pyrolysis reactions in the movpe of Ga2Se3 by in-situ gas sampling
N Maung, G H Fan, T L Ng, J O Williams and A C Wright
Journal of Crystal Growth, (1996), 158, no.1-2, 68-78
Homogeneous thermal-decomposition of dimethylzinc in a metal-organic
vapor-phase epitaxy reactor - an ex-situ investigation by FTIR absorption-spectroscopy
G H Fan , N Maung, T L Ng, J O Williams and A C Wright
Journal of the Chemical Society -Faraday Transactions, (1995), 91, No.19, 3475-3479
Metal-Organic Vapour Phase Epitaxial Growth of Cubic Gallium Selenide, Ga2Se3
T L Ng, N Maung, G Fan, I B Poole, J O Williams, A C Wright, D F Foster and D J Cole-Hamilton
Chemical Vapour Deposition (1996) 2, number 5, 185-189
Thermal decomposition of DtBuSe and DMZn in an MOVPE reactor system
G H Fan, N Maung, T L Ng, P F Heelis, J O Williams, A C Wright, D F Foster and D J Cole-Hamilton
J. Crystal Growth. 1997, 170, No.1-4, 485-490.
Presented at ICMOVPE VIII, Cardiff, 1996
Growth studies by Reflectance Anisotropy Spectroscopy (RAS) on MOVPE grown ZnSe
D Gnoth, I B Poole, T L Ng, D A Evans, N Maung, J O Williams and A C Wright
J. Crystal Growth. 1997, 170, No.1-4, 198-202.
Presented at ICMOVPE VIII, Cardiff, (1996)
MOVPE growth of Magnesium Cadmium Sulphide: Rocksalt of Sphalerite?
I B Poole, T L Ng, N Maung, J O Williams and A C Wright
J. Crystal Growth. 1997, 170, No.1-4, 528-532.
Presented at ICMOVPE VIII, Cardiff, (1996)
Metal-Organic Chemical Vapour Deposition for the preparation of new materials and interfaces
J O Williams, N Maung and A C Wright
Chapter 11 from 'Interfacial Science'. A 'Chemistry for the 21st Century' monograph. Blackwell Science.
Dynamic vapour pressure measurements of di-tertiarybutyl sulphide using an ultrasonic monitor
L D Stockton , T L Ng, N Maung, I B Poole, J O Williams, A C Wright, D F Foster, D J Cole-Hamilton
Journal of Crystal Growth, (1998), 183, No.1-2, pp.95-98
Growth of MgS by MOVPE: The Choice of Sulphur Precursor
L. D. Stockton, T. L. Ng, N. Maung and A C Wright
J. Mater. Sci: Materials in Electronics, (1998), 9, Number 3, pp.207-210
Direct synthesis of II3-V2 compound semiconductors by the Heterovalent Exchange Mechanism
A C Wright, T L Ng and N Maung
Philos. Mag. Vol. A79, No.11 (1999) 2691-2710
A study of the mechanism of the reaction of trimethylgallium with hydrogen selenide
N Maung, G Fan, T-L Ng, J O Williams and A C Wright
J. Mater. Chem., (1999), 9, 2489-2494
Unusual binary optical reflectivity of highly structured epitaxial gallium selenide thin films
A C Wright, T L Ng and N Maung
Advanced Materials, 12 (2000) 273-276
- Microscopy of materials
Detection of compound formation at the ZnSe/GaAs interface using high resolution transmission electron microscopy (HRTEM).
A C Wright and J O Williams
Journal of Crystal Growth, J Crystal Growth 114 (1991) 99-106
Growth and structural characterisation of molecular beam epitaxial erbium-doped GaAs
I Poole, K E Singer, A R Peaker and A C Wright
J. Crystal Growth 121 (1992) 121
Self-organising growth of erbium arsenide quantum dots and wires in gallium arsenide by molecular beam epitaxy
K E Singer, P Rutter, A R Peaker and A C Wright
Applied Physics Letters, 64 (1994) 707
Two beam high resolution dark-field imaging: Applications to epitaxial semiconducting materials
A C Wright and J O Williams
Proc. Conf. Microscopy of semiconducting materials (1993). Oxford University
IOP publishing. Conference series No. 134; section 1, pages 51-54
Structural characterisation of luminescent Ca0.95Cd0.05S
A C Wright, I V F Viney, B Ray, J Britewell and B W Arterton
J. Materials Science: Materials in Electronics 7 (1996) 305-308
Orientation dependent growth of TmAs wires in GaAs grown by MBE
A C Wright, M R Bennett and K E Singer
Proc. conf. Microscopy of semiconducting materials -10 (1997). Oxford University 7-10 April
IOP publishing, Bristol. Conference series No. 157 ; section , page 385-388.
MOVPE Growth of ZnSe: The effect of initiation conditions -a study by TEM
A C Wright, D N Gnoth, T L Ng and N Maung.
Applied Surface Science. Volumes 123/124 (1998) 555-559
Microstructure of Zinc Selenide single crystals grown by Solid Phase Recrystallisation
A C Wright
J. Crystal Growth, Vol. 203 No. 3 (1999) 309-316
Artefacts in Iodine-Ion milling of some compound semiconductors
A C Wright
Ultramicroscopy, Vol. 83 (2000) 1-8
A structural evaluation of ZnS-based electroluminescent phosphors and devices: a comparison with performance
A C Wright and I V F Viney
Philos. Mag. B, Vol. 81 No. 3, (2001), 279-297
On the origin of compositional fluctuations in ZnSe1-xSx alloys grown by metal-organic vapour phase epitaxy
A C Wright and N Maung
Philos. Mag. Vol. 83 No. 22, (2003) 2641-2652 (PDF)
Two-component dendritic gels: Easily tunable materials
A R Hirst, D K Smith, M C Feiters, H P M Geurts and A C Wright
J. AMERICAN CHEM. SOC. Vol. 125 (30) (2003) 9010-9011 (doc). Supplementary material (doc)
Oligomerisation and neurotoxicity of the amyloid ADan peptide implicated in Familial Danish Dementia
V Lelyveld, N Gunasekera, M Lee, G Gibson, O M A El-Agnaf, A C Wright and B Austen. J. Neurochemistry 88(2) (2004) 281-290 (doc).
An Ab Initio and Density Functional Theory Study of the Trimethylgallium- Hydrogen Selenide Adduct: (CH3)3Ga:SeH2,
N Maung, Journal of Molecular Structure (THEOCHEM), (1998), 432, 129-137
An Ab Initio and Density Functional Theory Study of the Dimethylzinc- Hydrogen Selenide Adduct: (CH3)2Zn:SeH2,
N Maung, Journal of Molecular Structure (THEOCHEM), (1998), 434, 255-264
The evaluation of bond dissociation energies for simple sulphur containing molecules using ab initio and density functional methods
N Maung, Journal of Molecular Structure (THEOCHEM), (1999), 460, No.1-3, pp.159-166
Studies of the thermal and photochemical decomposition mechanisms of But2Se in the presence of Me2Zn using deuterium labelled analogues
N L Pickett, D L Foster, N Maung and D J Cole-Hamilton
J. Materials Chemistry, 9 (1999) 3005-3014
Tel. 01978 293369 (+44 1978 293369)
Fax 01978 290008 (+44 1978 290008)
Email:The pages on this site are maintained by -Andy Wright- and were last modified on 11th December 2012
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