Research objectives and content
The research proposed here is a continuation of the research undertaken under fellowship No. BRE2CT943094, and is associated with and complementary to the Brite Euram II VAPOUR*CRYST programme, Contract No. BRE2CT940609.
Research under the last fellowship helped to develop a closed space vapour growth system for bulk CdTe crystals. Massflow control of the gaseous Cd and Te2 species and the possibility of controlling the shape of the crystal during growth were studied. It is intended to develop the system in order to monitor and control the ratio of vapour species during growth. Preliminary experiments have shown that absorption of light by Cd atoms and Te2 molecules is proportional to the partial pressure of these elements, and this provides the means for direct monitoring of the partial pressures. Furthermore, the ratio of Cd to Te2 species, which is a critical parameter if stable growth is to be obtained, may be monitored during the entire growth run. Post-growth characterisation of the grown crystals and comparison with the results from the partial pressures monitoring studies will allow the occurrence of defects, such as inclusions, precipitates, twins, etc. to be correlated with growth conditions.
Training content (objective, benefit and expected impact)
The applicant is currently registered for a Ph.D. degree and the award of this fellowship would enable the candidate to complete his Ph.D. studies. The success of these studies would allow the reproducible and economical growth of high quality crystals for use in compact, solid state detectors such as infrared, X-Ray and y-Ray detectors with applications in the electronic industry, medical and industrial screening and astronomy respectively.
Links with industry / industrial relevance (22)
Four companies (GEC-Marconi Infrared Ltd., MCP Wafers Technology Ltd., Thomas Swan Ltd. from UK and ENIRISORSE from Italy) are industrial partners in the VAPOUR*CRYST program. They have shown interest in the production and commercialisation of both, the growth system and the resulting CdTe crystals. MCP Wafers Ltd. has shown special interest in the monitoring of partial pressures, since the technique may be useful for monitoring vapour pressures in their existing production growth systems.