Lattice parameter and microhardness investigations on CdTe1-xSex

CdTe1-xSex anion mixed crystals have been grown from non-stoichiometric mel ts and by means of a modified vertical travelling-heater method. Selenium h as been found to have an essentially higher affinity for cadmium than tellu rium. The cubic phase (zincblende structure) exists in the composition rang e 0 less than or equal to x(CdSe) less than or equal to 0.45, the hexagonal phase (wurtzite structure) in the range 0.65 less than or equal to x(CdSe) less than or equal to 1. In order to compare the lattice parameters of the cubic and hexagonal modifications, the mean distances between next-neighbo uring anions and cations, d(a-c), were calculated from the lattice paramete rs. The relation between d(a-c) values and composition x roughly obeys Vega rd's rule. By means of Vickers indentation microhardness measurements, the solid-solution hardening (SSH) behaviour was investigated for the first tim e and has been compared with the SSH of II-VI cation solid solutions. Regar ding the hexagonal CdTe1-xSex modifications, one has to pay attention to th e large anisotropy of microhardness depending on the surface orientation. ( C) 1998 Kluwer Academic Publishers.