After 2.5MeV  in situ  electron irradiation at 4.2K, a photoluminescence optically detected magnetic resonance study was made of Zn vacancies (VZn), Zn interstitials (Zni), and some 25 distinct VZn-Zni Frenkel pairs with various lattice separations. The stability, photoluminescence energy, anisotropy of production as a function of beam direction, and exchange and dipole-dipole interactions in the excited emitting state, were measured for most of the pairs. By combining this information with data that had previously been determined for the isolated vacancy and interstitial, the electronic and lattice structures of the defects were established. The second-donor level (+/2+) for Zni was estimated to be located at Ec-0.9eV.

F.C.Rong, W.A.Barry, J.F.Donegan, G.D.Watkins: Physical Review B, 1996, 54[11], 7779-88