In-situ photoluminescence and capacitance-voltage characterization of InAlAs/InGaAs regrown heterointerfaces by molecular beam epitaxy

This paper characterizes the electronic properties of InAlAs/InGaAs molecular beam epitaxy (MBE) regrown interfaces by combined use of in-situ photoluminescence surface state spectroscopy (PLS³) and capacitance-voltage (C-V) techniques. It is shown that the interface state density at the continuously grown InAlAs/InGaAs interface is low and comparable with that of the uninterrupted AlGaAs/GaAs interface, and that the effect of the growth interruption was surprisingly small, whereas the same interruption resulted in almost 10² times reduction of the PL efficiency for the AlGaAs/GaAs system. It is also shown that a high density of surface states exists at the MBE InGaAs surface. Interruption after the growth of the bottom InAlAs layer in the InAlAs/InGaAs/InAlAs system also leads to appreciable generation of interface states, but it is much smaller as compared with the case of the AlGaAs/GaAs/AlGaAs system.