Photoluminescence of Yb3+-doped CuInS2 crystals in magnetic fields

Single crystals of Yb3+-doped CuInS2 were isolated by an In-flux technique. The Yb3+ concentration is estimated to be 4.5x10(19) cm(-3) in terms of the Curie-Weiss behavior of magnetic susceptibilities. The intra-4f-shell transitions of Yb3+ were resolved at low temperatures by photoluminescence peaks at 1.2-1.25 eV. The Yb-related peak intensities are weak in comparison with those arising from defect and impurity centers in the host. The magnetic field dependence of photoluminescence spectra shows interesting differences among the Yb-related peaks, with only part of them being Zeeman split. An energy level scheme on the basis of a single type of Yb3+ center in a tetragonal crystal field is proposed to explain the temperature- and magnetic-field dependence of the optical spectra. (C) 2001 American Institute of Physics.