PHYSICAL-PROPERTIES OF ALGAAS EPILAYERS SUBJECTED TO HIGH-PRESSURE-HIGH-TEMPERATURE TREATMENT

AlGaAs layers grown by molecular beam epitaxy on GaAs substrates were investigated before and after high hydrostatic pressure (1.2 GPa) at h igh temperature (770 K) treatment. In order to study the influence of high pressure - high temperature treatment on the physical properties of the AlGaAs layers, X-ray, electron transport and Raman scattering m easurements were performed at room temperature. The observed changes i n the lattice parameter, Raman spectra and free-carrier concentration were related to the strain relaxation and explained by the creation of misfit dislocations and other extended defects which were visible on the synchrotron X-ray topographs after high pressure - high temperatur e treatment.