Photoemission study of Au Schottky-barrier formation on GaSb, GaAs, and InP using synchrotron radiation

Abstract

Photoemission spectroscopy, constant-final-state spectroscopy, and ion-depth profiling techniques were applied to the study of the formation of Au Schottky barrier on cleaved GaSb, GaAs, and InP. It is found that the deposited Au interacts strongly with the semiconductors, causing decomposition of their surfaces. Further, the Fermi-level pinning is nearly complete at 0.2-monolayer Au coverage, when the Au is still "atomiclike." It is suggested that defect states at the interface are responsible for the Schottky-barrier pinning, and a mechanism for their creation is proposed. It appears that many of the known phenomena on Schottky barriers can be explained using a "defect" model proposed here.