High quality Al(Ga)As/GaAs/Al(Ga)As quantum wells grown on (111)A GaAs substrates

Abstract

We report the growth of high quality molecular beam epitaxy (MBE) AlGaAs, AlGaAs/GaAs/ AlGaAs, and AlAs/GaAs/AlAs multiple quantum wells (MQWs) on (111)A GaAs substrates. For (111)A AlGaAs/GaAs/AlGaAs MQWs, there is no detectable photoluminescence (PL) at a growth temperature of 640 degrees C, and narrow PL linewidth can only be obtained at growth temperatures higher than 680 degrees C. A PL linewidth of 13.8 meV is measured at the growth temperature of 720 degrees C. To understand such growth temperature dependence of (111)A MQWs, we have investigated the material quality of (111)A AlGaAs at different growth temperatures. The strong PL integrated intensity of 640 degrees C grown (111)A AlGaAs indicates good material quality and a low concentration of non-radiative recombination centers. However, the broad PL linewidth of 640 degrees C grown (111)A AlGaAs indicates the strong compositional modulation and a rough growth front. We have used AlAs instead of AlGaAs in order to reduce the compositional modulation and smooth the interface. A PL linewidth of 13.4 meV is measured for 640 degrees C grown (111)A AlAs/GaAs/AlAs MQWs, which is the narrowest value for (111)A MQWs. (C) 1996 American Institute of Physics.