Electronic properties of GaAs(100) surface passivated in alcoholic sulfide solutions

Using Raman spectroscopy and the Kelvin probe method the surface band bending and electron work function of GaAs(100) passivated in aqueous and alcoholic solutions of ammonium sulfide have been studied. It is shown that the solvent strongly affects the position of energy levels on the sulfide-treated surface. With the decrease of the solution dielectric constant the surface band bending decreases and the electron work function increases both in n-GaAs and p-GaAs. The ionisation energy of the semiconductor increases after sulfur treatment and in n-GaAs it increases with the decrease of the dielectric constant of the solution.