Schottky-barrier tunneling spectroscopy for the electronic subbands of a δ-doping layer

Abstract A sheet of donor atoms is embedded in GaAs only 200 A below the surface. The Schottky contact is used as a barrier for the tunneling curent between the subbands of the doping layer and the surface metal. The energies of occupied and unoccupied levels are determined from distinct structures in the first derivative. The comparison with a self-consistent calculation yields the densities of free carriers, δ-doping, and background doping.