A completely new design of vapour growth system was developed in the course of the project in which the mass transport and the crystal growth were decoupled from the temperature profile, allowing each to be set independently of the other. This was achieved tough the use of a flow restrictor between source and crystal and physically separating source and growth furnace zones, as described below. The system was built, commissioned and used to grow several crystals of CdTe, which were comparable in quality to what is currently available, but of larger diameter (50mm).
As an adjunct to this, a parallel study of a series of reference crystals obtained from a variety of laboratories was undertaken, to establish a base line crystal quality against which the performance of the Vapour*Cryst system could be compared. A considerable range of powerful techniques were brought to bear on establishing reference crystal quality.
A Focused Fundamental Research programme is proposed in order to establish the critical control parameters in the vapour transport nucleation and growth of CdTe. In addition it is intended to develop a model of the vapour growth and from a combination of experiments and modelling establish the optimum conditions for the preparation of high quality single crystals. A feature of the work will be a detailed characterisation study of the starting materials and the final crystals in order formulate a qualification specification for the singl crystals . A goal of the work will be to demonstrate an enabling technology for the development of an efficient commerciallyviable technology for the growth of CdTe and related optical, sensor and substrate materials.
Funding SchemeCSC - Cost-sharing contracts