Chemical and electronic properties of sulfur-passivated InAs surfaces

Treatment with ammonium sulfide ((NH4)(2)S-x) Solutions is used to produce model passivated InAs(001) surfaces with well-defined chemical and electronic properties. The passivation effectively removes oxides and contaminants, with minimal surface etching, and creates a covalently bonded sulfur layer with good short-term stability in ambient air and a variety of aqueous solutions, as characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and Hall measurements. The sulfur passivation also preserves the surface charge accumulation layer, increasing the associated downward band bending. (C) 2002 Elsevier Science B.V. All rights reserved.