COMPOSITIONAL DISORDERING OF ALGAAS/GAAS SUPERLATTICES BY USING THE LOW-TEMPERATURE-GROWN GAAS

Abstract

The use of low-temperature (similar to 200 degrees C) grown GaAs by molecular beam epitaxy to induce compositional disordering of AlGaAs/GaAs superlattices has been studied. After furnace annealing between 700 and 850 degrees C for 30 min, an obvious blue shift in the peak wavelength of the superlattice emission is observed by the 77 K photoluminescence (PL), indicating that the emission has been changed from that of the GaAs quantum wells to that of the intermixed AlGaAs. The PL shift and the depth profile of Al concentration measured by secondary ion mass spectrometry indicate that the superlattice is nearly totally disordered after 850 degrees C annealing. (C) 1995 American Vacuum Society.