LATTICE STRAIN NEAR INTERFACE OF MBE-GROWN ZNTE ON GAAS

Effects of growth temperature on optical properties in ZnTe on GaAs grown by molecular beam epitaxy (MBE) have been investigated by photoluminescence (PL) and Raman scattering. PL results show the decrease in Zn vacancies and in substitution of oxygen for excess Te as growth temperatures increase. An improvement in crystallinity of ZnTe is achieved by using ZnSe buffer layer. LO phonons of ZnTe shifted slightly to low frequencies and those of ZnSe largely to higher frequencies with respect to bulk values. Large compression of the ZnSe lattice and small elongation of the ZnTe lattice are explained by existence of misfit dislocations or Te associated precipitation near interface.