Infrared photoluminescence from TlGaS₂ layered single crystals

Abstract

Photolimuniscence (PL) spectra of TlGaS2 layered crystals were studied in the wavelength region 500-1400 nm and in the temperature range 15-115 K. We observed three broad bands centered at 568 nm (A-band), 718 nm (B-band) and 1102 nm (C-band) in the PL spectrum. The observed bands have half-widths of 0.221, 0.258 and 0.067 eV for A-, B-, and C-bands, respectively. The increase of the emission band half-width, the blue shift of the emission band peak energy and the quenching of the PL with increasing temperature are explained using the configuration coordinate model. We have also studied the variations of emission band intensity versus excitation laser intensity in the range from 0.4 to 19.5 W cm-2. The proposed energy-level diagram allows us to interpret the recombination processes in TlGaS2 crystals. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Raman spectroscopic investigations on transition‐metal dichalcogenides MX2 (M = Mo, W; X = S, Se) at high pressures and low temperature

“…[46][47][48][49][50][51][52][53][54] They show that the Raman shift can be successfully modeled by including the Table 1. Wavenumber and assignments of the phonon modes observed in the Raman spectrum of MX 2 single crystal using reference [13,[22][23][24][25][26][27] [29,[38][39][40] thermal expansion coefficient, [41,42] effects of thermal expansion and phonon-phonon coupling.…”

“…Wavenumber and assignments of the phonon modes observed in the Raman spectrum of MX 2 single crystal using reference [13,[22][23][24][25][26][27] [29,[38][39][40] thermal expansion coefficient, [41,42] effects of thermal expansion and phonon-phonon coupling. [49] In an isotropic system (such as cubic crystal), the phonon wavenumber ω = ω(V,T). Therefore, at a fixed pressure the total change in phonon wavenumber due to temperature is expressed as follows:…”

Electrical and optical properties of Co doped TlGaS2 crystals

“…The lattice of these crystals consists of alternating two dimensional layers arranged parallel to the (001) planes [2]. It has been reported that TlGaS 2 may crystallize in various polytypes due to the attachment of their layers.…”

Photoluminescence investigations and thermal activation energy evaluation of Fe3+-doped PVA films

“…In order to investigate the mechanisms governing the material emission, the integrated PL intensity as a function of the temperature inverse, for both pure and doped PVA films, was represented. In order to evaluate the thermal activation energy, the integrated PL intensity of the first three samples, pure PVA, 0.5 and 1 % doped films, was fitted using the Arrhenius model [19][20][21]:…”