A mechanism was presented, for the compensation of N acceptors, on the basis of first-principles pseudopotential calculations. It was found that, under Se-rich conditions, the formation of N2 molecules that were electrically inert neutralized the acceptor activity. The maximum acceptor density which could be achieved by using P dopants was about 1018/cm3; in good agreement with experimental data. Under Zn-rich conditions, the hole density was increased by an order of magnitude; thus offering the possibility of low-resistance p-type doping. However, self-compensation still occurred due to a [100] split interstitial N-N complex which occupied a Se site. This behaved like a double donor.

B.H.Cheong, C.H.Park, K.J.Chang: Physical Review B, 1995, 51[16], 10610-4