Strain-Induced Energy Shift of Photoluminescence Spectra in MOCVD-Grown ZnTe Films on (100) GaAs Substrates

Abstract

It has been revealed that heteroepitaxial ZnTe films grown on (100) GaAs substrates by low-pressure metalorganic chemical vapour deposition (MOCVD) receive considerably biaxial tensile stress. In order to characterize the effect of strains on the optical properties, the dependence of the 2.32 eV donor-acceptor pair and oxygen-bound-exciton emissions on film thickness was investigated in the range of 1 to 8 µm. It was found that photoluminescence (PL) peaks shift toward the lower-energy side and that full-width at half-maximum (FWHM) values of both PL and X-ray diffraction peaks decrease with increasing film thickness, suggesting that the film quality significantly depends upon its thickness.