The origin of gallium desorption transients during AlGaAs/GaAs heterointerface formation by molecular beam epitaxy

A Monte Carlo simulation study is performed to investigate the Ga desorption behavior at AlGaAs/GaAs heterointerfaces during growth by molecular beam epitaxy. The transients in Ga desorption rate upon opening/closing the Al shutter arise due to both the change in V/III flux ratio and the Al–Ga surface exchange mechanism. It is shown that the desired “steplike” variation in Ga desorption rate at each interface can be attained by a growth procedure employing a constant V/III flux ratio.