DEEP LEVELS IN UNDOPED AND ERCL3-DOPED TLGAS2 SINGLE-CRYSTALS

TlGaS2 and TlGaS2:ErCl3 single crystals were grown by the Bridgman tec hnique. The optical energy band gaps and the deep levels of the as-gro wn crystals were investigated by the optical absorption, thermally sti mulated current (TSC), and, photo-induced current transient spectrosco py (PICTS) spectra. The electron traps (0.18 +/- 0.01 eV and 0.23 +/- 0.01 eV) and the hole traps (0.36 +/- 0.02 eV and 0.66 +/- 0.02 eV) ar e observed in TlGaS2 single crystal. In the case of TlGaS2:ErCl3 singl e crystal, two deep levels as donors are located at 0.15 +/-0.01 eV an d 0.25 +/- 0.01 eV and, one deep level as acceptor, at 0.64 +/- 0.02 e V.