Band structure of Mg1-xZnxSySe1-y epitaxially grown on GaAs

Abstract

It has been shown that the experimental bandgap of an MBE-grown film of Mg1-xZnxSySe1-y may vary from 2.8 to about 4 eV while maintaining a lattice match to GaAs. Comparing this with the bandgap value of 2.7 eV for ZnSe, the alloy was proposed as a suitable material for the cladding layer of a ZnSe-based laser diode. In the present work, the relativistic band structure and band structure bowing factors of Mg1-xZnxSySe1-y epitaxially grown on GaAs are calculated by the ab initio pseudopotential method with spin-orbit correction. The calculated results are compared with experimental data on the same system. In the present calculation, local order with relaxation is considered. In contrast to calculation based on the virtual crystal approximation (VCA), the results show that there exists quite significant bowing in the bandgap of the alloy.