Effect of thermal annealing on optical emission properties of low-temperature grown AlGaAs/GaAs multiple quantum wells

We have investigated the effect of thermal annealing on optical emission properties of low-temperature (LT) grown AlGaAs/GaAs multiple quantum wells (MQWs) by using photoluminescence (PL) spectroscopy. For comparison, the results on normal-temperature (NT) grown MQWs implanted with protons are also presented. The LT sample was grown by molecular beam epitaxy at 310 degrees C. The as-grown LT-MQWs show moderately strong FL. Upon annealing at 600 degrees C, the PL intensity of the LT-MQWs is dramatically quenched, in sharp contrast to the large increase in PL intensity of the implanted NT-MQWs. The quenching of PL intensity in the LT-MQWs is attributed to the formation of arsenic clusters that fast trap photoexcited carriers. In addition, an enhancement in the interface intermixing and roughening induced by thermal annealing has also been observed in the LT-MQWs. (C) 1996 American Institute of Physics.