ATTEMPTS TO GROWTH OF UNDOPED CDTE SINGLE-CRYSTALS WITH HIGH ELECTRICAL-RESISTIVITY

In order to obtain undoped semi-insulating CdTe single crystals differ ent growth methods from the melt have been compared. A Cd excess of de lta gamma(Cd) = 5 x 10(-3)-1 x 10(-2) at% in the starting melt is requ ired for crystallization of a near stoichiometric composition. In hori zontal and vertical Bridgman techniques with controlled gas atmosphere a temperature difference between the free melt surface and Cd source of 300 and 270 degrees C, respectively, needs to be maintained. Maximu m electrical resistivities > 10(10) Omega . cm have been obtained in s haped crystals growth by a new casting technique in uncoated silica di es.