Electronic structure due to hydrogen and vanadium as substitutional impurities in InP

The self-consistent local-density theory is used in a cluster model to calculate the charge distribution, one-electron energy spectra, and the density of states for pure InP and for H and V substituted at the In site. The pure semiconductor gap is found to be 0.8 eV, consistent with experiments. The hydrogen impurity introduces a trapping center at Ev+0.37 eV in the gap regiona semi-insulating-like behavior. The transition metals are generally found to introduce deep levels in the gap region, but for vanadium we find the gap swept clean of any impurity level, with the last partially occupied state close to the bottom of the conduction band. This is consistent with deep-level transient spectroscopy experiments where no vanadium-related deep levels in the band gap are found down to 4 K.