Deep levels in GaAs grown by atomic layer molecular beam epitaxy

We present a study on deep levels in GaAs:Si grown by atomic layer molecular beam epitaxy (ALMBE). We show that in ALMBE GaAs grown at temperatures TS in the range 370-530 °C, the deep level concentrations: (i) are up to 3 orders of magnitude smaller than those of material grown by molecular beam epitaxy (MBE) at similar temperature ranges, and (ii) can be compared to those of GaAs grown by MBE at 600 °C. These features are independent whether Si is supplied during: (a) both the Ga and As subcycles, (b) the As subcycles, or (c) the Ga subcycles. Therefore, as for deep levels, ALMBE GaAs grown at 370<=TS<=530 °C can be related to GaAs prepared by MBE at conventional temperatures