In-situ reflectometry and RDS monitoring of atomic layer MBE of ZnSe and ZnTe on GaAs

We investigated the growth of ZnSe and ZnTe on GaAs(OOl) by reflectometry and reflection difference spectroscopy (RDS) during an MBE process. Images of RHEED diffraction patterns were recorded along with the optical observations. The in-situ GaAs-substrate preparation and its effect on the optical response of the surface both after deoxidation with hydrogen as well as after thermal annealing was analyzed. Spectra at various stages of growth were measured and fitted with a multiple-layer model. Furthermore, the influence of surface stoichiometry on the RD-spectrum was investigated and a real-time monitoring of the RD-signal was performed.