Photoemission investigation of Sb/GaAs(110) interfaces

The Sb/GaAs(110) interface prepared at room temperature (RT) and low temperatures (LT, 150 and 80 K) has been studied using photoelectron spectroscopy (PES). At both RT and LT, Sb overlayer grows on GaAs(110) surface in Stranski-Krastanov mode, and similar Fermi level pinning patterns as well as the final pinning positions have been observed, which is drastically different from that at other metal/GaAs interfaces (e.g. Al/GaAs). The effects of annealing on the Sb/GaAs interface has also been studied. A large movement of the Fermi level towards the valence band maximum (VBM) for p-type GaAs and essentially no movement for n-type GaAs after Sb/GaAs interface annealing have been observed, thereby casting doubt on the prior explanation solely on the basis of Sb/p-GaAs annealing study [J. Vacuum Sci.Technol. B 5 (1987) 1048; Phys. Rev. B 36 (1987) 1328]. The findings are discussed in terms of various models of Schottky barrier formation.