Photoemission measurements of quantum states in accumulation layers at narrow band gap III-V semiconductor surfaces

Tiny amounts of cesium adsorbed on cleaved InSb(110) surfaces result in a s trong downward band bending (BB) and creates a two-dimensional (2D) electro n channel in the sub-surface region. For the first time, electron emission arising from this channel was observed for this material. We compare it to the similar situation mit previously with InAs(110). in this last case, new high-resolution measurements allow to determine the dispersions of the qua ntized energy levels, and to derive the average effective mass of the carri ers in the channel. For both systems, self-consistent calculations and mode l-function curve fittings support the experimental results. (C) 2000 Elsevi er Science B.V. All rights reserved.