Bismuth flux dependence of GaAsBi/GaAs MQWs grown by molecular beam epitaxy using two-substrate-temperature technique

Abstract

Multi-quantum wells (MQWs) of GaAsBi/GaAs were grown by molecular beam epitaxy (MBE) and dependence of its surface morphology, Bi content and optical properties on Bi beam equivalent pressure (BEP) were studied. For the MQWs growth, two-substrate-temperatures (TST) technique was used, where GaAsBi layers were grown at TGaAsBi=350 °C and GaAs layers at TGaAs=550 °C. The segregated bismuth atoms were desorbed by increasing the substrate temperature from TGaAsBi to TGaAs after finishing the growth of each GaAsBi layer of MQWs including the topmost GaAsBi layer. The surface of the topmost GaAsBi layer shows no sign of Bi droplet formation even for the MQWs grown at highest Bi supply. The Bi content increases up to 3.8% in proportional to the Bi BEP and decreases in a higher Bi BEP region.