Electron spin resonance study of electron-irradiated ZnS crystals containing stacking faults

Three kinds of photosensitive ESR signals (V1, V2, F) have been found to be produced by electron irradiation. Signals V1 and V2 (V1 having g sub(parallel) = 2.0030, g sub(perpendicular) = 2.0550, and axial symmetry along the twinning [111]sub(w) axis; V2 having g sub(parallel) = 2.0030, g sub(perpendicular) = 2.0530, and axial symmetry along another <111> axis) are ascribed to Zn vacancies (V centers) situated at atacking faults; V1 is due to a hole localized on the S ion next to the Zn vacancy along the [111]sub(w) axis; V2 is due to a hole localized on one of the other three S ions next to the Zn vacancy. The signal F (g = 2.0027 and isotropic) is ascribed to F centers. The excitation, quenching, and enhancing bands of the V centers are around 2.85 eV, 1.8 eV, and 1.3 eV, respectively. For F centers the excitation bands are around 3.4 eV and 1.8 eV, while the quenching bands are around 2.8 eV and 2.1 eV. A band model is proposed to interpret these photosensitivities. (author)