The effect of the surface Fermi level pinning on the properties of δ-doped systems

Electronic potential profile, energy levels, and their respective occupations are self-consistently calculated for δ-doped semiconductor films, taking into account the charge depleted by the surface. This effect is considered by requiring the Fermi level at the surfaces to be at some fixed value relative to the band gap edges. The electron concentration in the potential well is calculated for different values of the film thickness and of the surface chemical potential. The results show that these calculations can be helpful in determining the Fermi level pinning at the surface by fitting Hall concentrations of δ-doped samples.