Untersuchungen an paramagnetischen Zentren in selbstaktivierten kubischen ZnS-Einkristallen

Abstract

Combined optical and EPR investigations have been performed on the Fe3+- and the A-center in synthetic cubic ZnS crystals. The Α-center is believed to be the center responsible for the selfactivated blue luminescence of ZnS. The Α-center is oriented along the [111] axis of the cubic crystal. Its g-factor has axial symmetry with g∥ = 2.0530 ± 0,0003 and g⊥= 2,0286 ± 0,0003 . Both centers appeared after excitation with uv at 77 °K and could be removed or enhanced by visible and near infrared radiation. The spectral response of quenching and generation was investigated between 0.3 and 2.0 μ. Quenching maxima occured near 0.75 - 0.80 μ for the Α-center and near 0.57 and 1.2 μ for the Fe3+ ion. The observations are interpreted by hole excitation and hole transfer between the two centers