Photoconductivity and luminescence anisotropy in ZnIn2S4 and ZnIn2S4:Cu2+ single crystals

ZnIn 2 S 4 and ZnIn 2 S 4 :Cu 2+ single crystals are shown to exhibit considerable photoconductivity and luminescence anisotropy. The mechanism of carrier recombination in the crystals is polarization-dependent. Their spectra can be understood in terms of optical transitions involving donor and acceptor levels. The degree and spectral distribution of the anisotropy can be tuned via doping and alternating growth of the three- and one-layer polytypes.