PHOTOEMISSION INVESTIGATION OF THE 2D ELECTRON-GAS CREATED AT THE INAS(110) SURFACE

On InAs(110) surfaces a downward band bending (BB) was produced either by cleavage defects or by adsorption of very small amounts of Cs atom s. As a consequence the Fermi level was moved high into the conduction band, resulting in the formation of a two-dimensional electron channe l (2D-EC). Electron emission arising from this channel was detected by angle-resolved photoelectron spectroscopy near the <(Gamma)over bar> points of the first and second surface Brillouin zones. We present a d etailed investigation of the corresponding photoemission characteristi cs using tunable low energy synchrotron radiation light. We find in pa rticular that the photoemission intensity depends drastically on the p hoton energy. This effect is interpreted as resulting from the quantiz ation of the 2D electron gas in the direction normal to the surface it is directly linked to the electron density sampled (i.e. the depth pr obed) beneath the top surface.