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.