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

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 °C, and narrow PL linewidth can only be obtained at growth temperatures higher than 680 °C. A PL linewidth of 13.8 meV is measured at the growth temperature of 720 °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 °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 °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 °C grown (111)A AlAs/GaAs/AlAs MQWs, which is the narrowest value for (111)A MQWs.