Deep level transient spectroscopy investigation of GaAs grown by atomic layer molecular beam epitaxy

We report on deep level incorporation in GaAs grown by atomic layer molecular beam epitaxy (ALMBE). In contrast to the case of MBE GaAs, where the main features of the deep level transient spectra strongly depend on the growth temperature T S for 370⩽T S ⩽530 ° C , GaAs grown by ALMBE shows only three peaks, which correspond to the M1, M3 and M4 levels typical of MBE GaAs, together with a fourth trap, that we label M(330). The concentrations of these levels are comparable with those measured in MBE GaAs grown at 600°C and are weakly dependent on T S , in any case being smaller than 1.7×10 13 cm −3 ; these values are up to three orders of magnitude lower than those observed in MBE GaAs grown at comparable temperatures. Thus, as far as deep levels are concerned, ALMBE GaAs grown at 370⩽T S ⩽450° C can be compared with GaAs grown MBE at conventional temperatures (about 600°C).