Akademik Veri Yönetim Sistemi
CRYSTAL RESEARCH AND TECHNOLOGY, cilt.43, sa.5, ss.514-521, 2008 (SCI-Expanded)
Photoluminescence spectra of Tl4GaIn3S8 layered crystals grown by Bridgman method have been studied in the wavelength region of 500-780 nm and in the temperature range of 26-130 K with extrinsic excitation source (lambda(exc) = 532 nm), and at T = 26 K with intrinsic excitation source (lambda(exc) = 406 nm). Three emission bands A, B and C centered at 514 nm (2.41 eV), 588 nm (2.11 eV) and 686 nm (1.81 eV), respectively, were observed for extrinsic excitation process. Variations in emission spectra have been studied as a function of excitation laser intensity in the 0.9-183.0 mW cm(-2) range for extrinsic excitation at T = 26 and 50 K. Radiative transitions from the donor levels located at 0.03 and 0.01 eV below the bottom of the conduction band to the acceptor levels located at 0.81 and 0.19 eV above the top of the valence band were proposed to be responsible for the observed A- and C-bands. The anomalous temperature dependence of the B-band peak energy was explained by configurational coordinate model. From X-ray powder diffraction and energy dispersive spectroscopic analysis, the monoclinic unit cell parameters and compositional parameters of Tl4GaIn3S8 crystals were determined, respectively. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.