SELF-COMPENSATION IN NITROGEN-DOPED ZNSE

The structural and electronic properties of column V acceptor impurities in ZnSe are reviewed with special emphasis on N. The results of our calculations indicate that As and P acceptors possess two atomic configurations: a metastable effective-mass state with a small lattice relaxation and a stable deep state with a large lattice relaxation. Substitutional N gives rise to shallow acceptor states in either configuration. The low 20-30% doping efficiency is proposed to be caused by N bonding at interstitial sites. Various interstitial bonding configurations are found to give both shallow donor and shallow acceptor states leading to self-compensation. Post growth in diffusion of N is proposed to be useful in increasing the concentration of shallow acceptor states.