Effects of Zn to Te ratio on the molecular-beam epitaxial growth of ZnTe on GaAs

Abstract

ZnTe films have been grown with Zn:Te flux ratios ranging from 1 to 3.2. The highest quality films have been grown with flux ratios between 2 and 3, substrate temperatures between 300 and 325 °C, and a surface reconstruction that is a combination of c(2×2) and (2×1). Films grown under these conditions have x-ray rocking curve half-widths between 125 and 225 arcsec. Photoluminescence spectra show that the relative intensity of emission related to Zn vacancies decreases with increasing Zn:Te ratio. Picosecond photoconductivity measurements show an initial decay rate for photoexcited carriers that correlates well with other material parameters. After several hundred picoseconds, the decay rates for different samples show exponential behavior with a lifetime of approximately 675 ps.