Photoemission study of sputter-etched InP surfaces

Abstract

The effects of sputter etching and subsequent surface treatments including thermal annealing and oxygen exposure on n-InP surfaces have been studied by measuring the photoemission spectra using both Al Kα and synchrotron radiation. Results indicate that sputtering with Ar+ at 1–3 keV and low current density leaves an In-rich surface (In/P=2) and, from the movement of the Fermi level relative to the conduction-band minimum, is seen to introduce acceptor-type defects. Annealing of the surface causes dissolution of some excess In into the bulk as well as removal of some of these defects. The behavior of the annealed surface to oxygen exposure is similar to that of the cleaved surface with the creation of donor defects.