Trends in temperature-dependent Schottky barrier formation: The Ga/GaAs and Mn/GaAs interfaces

Abstract

We use soft x-ray photoemission spectroscopy to study the Ga/GaAs and Mn/GaAs interfaces formed at room temperature (RT) and at low temperature (LT=80−100 K). The LT Ga/GaAs interface exhibits the strongly inhibited clustering observed at other nonreactive metal/GaAs interfaces. The Mn–GaAs reaction is slowed somewhat. At both interfaces, the effect of temperature on EF movement is in accord with the trends previously set: initial band bending on n-GaAs is slowed at LT, whereas band bending on p-GaAs is not affected significantly. For both Ga and Mn/GaAs, EF movement at low coverages is consistent with the explanation proposed for the sp and noble metals: introduction of donor states from, e.g., the specific adsorbate levels. Studies of the noble metal interfaces with GaAs have showed that the establishment of the final EF position is related to the appearance of metallicity at the interface; Mn/GaAs provides direct evidence for that interpretation.