Photoluminescence in Ho-doped AgGaS2 single crystals

Doping of Ho into AgGaS2 has been carried out by the thermal diffusion of H o element into the undoped crystal. Sharp photoluminescence (PL) lines rela ted to the S-5(2) --> 5I(8) and F-5(3) --> I-5(7) transitions in the Ho3+ i on are observed in the energy regions 2.23-2.28 and 1.85-1.93eV, respective ly. Temperature dependence and excitation wavelength dependence of the PL i ndicate the existence of at least four types of He-related luminescence cen ters. Moreover, it is found that PL lines from different He-related lumines cence centers exhibit different excitation and recombination mechanisms. (C ) 2000 Elsevier Science B.V. All rights reserved.