Structural and optical properties of InAs quantum dots regrown on atomic hydrogen-cleaned GaAs surface

We report the structural and optical properties of InAs quantum dots (QDs) directly regrown on air-exposed and subsequent atomic hydrogen-cleaned (AHC) GaAs (001) surface. The average size of InAs QDs on the AHC GaAs surface is 29nm, which is larger than 22nm for the conventionally grown InAs QDs on GaAs. The integrated photoluminescence intensity of the InAs QDs on the AHC GaAs measured at room temperature is larger than that of the reference sample by two orders, even though the cleaned GaAs surface directly faced the base of the InAs QDs. The decrease in the interface states between the wetting layer and AHC GaAs was confirmed by Franz–Keldysh oscillations of the photoreflectance spectra.