CHARGE ACCUMULATION AT INAS SURFACES

Angle-resolved photoelectron spectroscopy has been used to directly pr ove the existence of a charge accumulation layer at clean InAs surface s. The formation of an accumulation layer is shown to be a common prop erty of polar InAs surfaces, with the precise surface Fermi level posi tion above the conduction band minimum determined by the surface geome try. The emission from states in the accumulation layer is studied wit h respect to its photon energy and angular dependence.