STRUCTURAL AND CONDUCTIVITY TYPE TRANSITIONS IN VAPOR-PHASE GROWN (ZNTE)X(CDSE)1-X SINGLE-CRYSTALS

(ZnTc)x(CdSe)1-x single crystals have been prepared by vapour phase gr owth technique. ZnTc crystals are p-type with zincblende structure, wh ereas CdSe crystals are n-type with wurtzite structure. In mixed cryst als of (ZnTe)x(CdSe)1-x n-type conductivity with wurtzite structure is observed for x less-than-or-equal-to 0.4 whereas only p-type conducti vity with zincblende structure is observed for x greater-than-or-equal -to 0.5. The structural transition is obvious for 0.4 < x < 0.5 and th e lattice parameters are found to vary linearly with composition withi n each structure. The structure and conductivity type transitions are attributed to a strong auto-compensation phenomenon in II-VI alloy sys tems.