A survey of potential shallow n-type donors was carried out by using the atom superposition and electron delocalization molecular orbital method. Electronic structures and defect stabilities were estimated for N, P, O, S, F and Cl in substitutional mono-vacancy sites, and for I, Xe, and atom pairs (BO, BS, NO, NS, BeCl) in substitutional di-vacancy sites. The calculations indicated that the BS, NS and BeCl pairs, and I, in di-vacancy sites could provide shallow donor levels, and might be more stable than P in a mono-vacancy site.

A.B.Anderson, E.J.Grantscharova, J.C.Angus: Physical Review B, 1996, 54[20], 14341-8