It was recalled that the nature of the so-called deep donor, which appeared at a depth of about 0.05eV when ZnSe was doped with N, remained a matter of controversy. The centre was of importance because it appeared to act as a compensating centre which was at least partly responsible for the difficulty in obtaining effective acceptor concentrations of above 1018/cm3. The most popular model involved a Se vacancy which was associated with a substitutional N atom. Although recent total-energy calculations supported this model, no conclusive evidence existed. Electrons which were trapped by the centre had a gyromagnetic ratio of 1.38. This contrasted with the value of 1.11 for electrons which were bound at normal shallow (0.026eV) donors. In order to obtain a better understanding of the centre, spin-flip Raman scattering experiments were used to determine how this g-value depended upon the composition of the N-doped ternary alloy, ZnSxSe1-x, for x-values ranging from 0 to 0.1. It was found that the g-value remained constant; unlike that of shallow donors, which increased by 0.12 over the same composition range. It was noted that any microscopic model had to be reconciled with this invariance.

The Gyromagnetic Ratio of the Compensating Donor Centre in Nitrogen-Doped ZnSSe K.Ogata, J.J.Davies, D.Wolverson, S.Fujita, S.Fujita: Semiconductor Science and Technology, 2000, 15[2], 209-13