The structural and electronic properties of column-V acceptor impurities were reviewed with special emphasis on N. The results of calculations indicated that As and P acceptors possessed 2 atomic configurations. These were a metastable effective-mass state with a small lattice relaxation, and a stable deep state with a large lattice relaxation. Substitutional N gave rise to shallow acceptor states in either configuration. A low (20 to 30%) doping efficiency was attributed to N bonding at interstitial sites. Various interstitial bonding configurations were found to give both shallow donor and shallow acceptor states which led to self-compensation.

D.J.Chadi, N.Troullier: Materials Science Forum, 1993, 117-118, 61-6