Before joining Heriot-Watt in 1975, I worked on the vacuum evaporation of CdS and CsSe for thin-film devices such as solar cells, and on the synthesis, growth and doping of ZnSe crystals for light-emitting diodes.
At Heriot-Watt I first investigated Schottky diodes on crystalline semiconductors and then thin-film amorphous silicon, for solar cells; we reported the first UK amorphous silicon solar cell in Nature (1978).
This led to the development of a plasma chemical vapour deposition unit for hydrogenated thin-film alloys of silicon. These materials were then used for electrical and optical devices and provided work for several successful PhD students.
This work was extended to high power RF plasma deposition of infrared transmitting glasses (GeS and GeSe), supported by BTRL and Barr & Stroud.
Lasers were used to process some of these materials and gave rise to a new research activity; the crystallization, oxidation and ablation of semiconductors was extended to the deposition of materials from gases.
Consequently various electrical and optical materials were deposited in the required pattern for devices from laser-heated gases. New organic sources of metals were prepared by the Department of Chemistry.
The award of a substantial SERC grant for the growth of diamond thin-films in 1988 also involved members of several other Universities in a Group that had existed for two years. (This Universities Carbon Films and Materials Group had industrial sponsors and acted as an information source, prior to applying for a series of research grants.) Our many subsequent EPSRC awards led to advances in CVD diamond: first microwave plasma CVD equipment in the UK; first academic group worldwide to grow hetero-epitaxial diamond; first demonstration of selective area growth using 'lift-off' techniques; first demonstration of surface attachment onto diamond for active glucose sensors; first demonstration of cavity ring down spectroscopy (CRDS) for ultra-sensitive detection of reactive intermediates in a microwave plasma; first demonstration of homogeneous nucleation to synthesise nanoparticle diamond.
A patent application was filed in 1992 by BTG, assigned by P John, I C Drummond and myself, for a method of nucleating diamond growth.
A joint EPSRC project with the Department of Chemical & Process and Mechanical Engineering and with two industrial partners investigated plasma coatings for drop-wise condensation coatings on steam boiler tubes.
A series of investigations into the structure of various thin film materials has made use of the XPS facilities at RUSTI, Daresbury Laboratories, and I served on the EPSRC review panel of RUSRI.
Plasma treatment of textiles for medical uses, and of other textile-related products, including pigments, was a more recent development in cooperation with the School of Textiles at Heriot-Watt and local industries.
Some of these topics are now converging in a means of fabricating flexible nanocrystalline silicon solar cells on textile substrates, for which a "due diligence" exercise was completed by Building Research Establishment for Scottish Enterprise Lanarkshire prior to seeking commercial funding.
A major grant was awarded by EPSRC in 2007 to
lead an investigation of diamond coatings for plasma-facing components
in tokamak fusion reactors. Partners include UKAEA Culham and materials
modeling at University College London.
