ELECTRONIC STATES INDUCED BY A GA VACANCY IN THE GAAS1-XPX ALLOY

Self-consistent one-electron state calculations are carried out, for t he first time, for a gallium vacancy in the GaAs1-xPx alloy. The clust er model, within the framework of the multiple-scattering X alpha theo ry, is used to calculate several charge states of the vacancy. Suitabl e clusters have been considered in order to simulate the phosporous co ncentration x in the alloy and how the nearest-neighbors configuration s affect the vacancy-related levels. It is found that the defect intro duces a deep energy level into the band gap which follows the host-val ence band edge as x varies. The same trend in donor and acceptor level s is observed, with a very small Mott-Hubbard potential energy. (C) 19 93 John Wiley & Sons, Inc.