Vacuum ultraviolet photoelectron spectroscopy of (NH4)2S-treated GaAs (100) surfaces

Abstract

The surface chemistry and band bending of the ammonium sulfide-treated GaAs (100) surface has been studied using surface-sensitive synchrotron radiation photoemission spectroscopy. We find that the treatment leaves the GaAs surface terminated with roughly a monolayer of sulfur bonded to both As and Ga atoms. An n-type barrier height of 0.8 eV is measured. The thermal stability of the various chemical components is studied and various issues of the passivating mechanism are discussed.