Multiphonon absorption processes in layered structured TlGaS2, TlInS2 and TlGaSe2 single crystals

Hasanlı, Nızamı
The infrared transmittance and Raman scattering spectra in TlGaS2, TlInS2 and TlGaSe2 layered single crystals grown by Bridgman method were studied in the frequency ranges of 400-1500 and 10-400 cm(-1), respectively. Three, three and five bands observed at room temperature in IR transmittance spectra of TlGaS2, TlInS2 and TlGaSe2, respectively, were interpreted in terms of multiphonon absorption processes. (C) 2013 Elsevier By. All rights reserved.


Optical constants of Tl4Ga3InSe8 layered single crystals
Goksen, K.; Hasanlı, Nızamı (Elsevier BV, 2007-11-15)
The optical properties of Tl(4)Ga(3)lnSe(8) layered single crystals have been studied by means of transmission and reflection measurements in the wavelength range of 500-1100 run. The analysis of the room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 1.94 and 2.20 eV, respectively. Transmission measurements carried out in the temperature range of 10-300 K revealed that the rate of change of the indirect band gap with temperature i...
Radiative donor-acceptor pair recombination in TlInS2 single crystals
Aydinli, A; Hasanlı, Nızamı; Yilmaz, I; Serpenguzel, A (IOP Publishing, 1999-07-01)
Photoluminescence (PL) spectra of TlInS2 layered single crystals were investigated in the 500-860 nm wavelength region and in the 11.5-100 K temperature range. We observed two PL bands centred at 515 nm (2.41 eV, A band) and 816 nm (1.52 eV, B band) at T = 11.5 K and an excitation intensity of 7.24 FV cm(-2). A detailed study of the A band was carried out as a function of temperature and excitation laser intensity. A red shift of the A band position was observed for both increasing temperature and decreasin...
Hasanlı, Nızamı; MELNIK, NN; RAGIMOV, AS (Wiley, 1983-01-01)
Measurements are made of polarized Raman scattering and infrared reflection spectra of twenty two compositions of GaS1‐xSex layer mixed crystals grown by the Bridgman method. Besides the usual one‐mode and two‐mode behaviours of phonon modes, a number of more complex dependences characterized by the appearance of additional bands in the spectra of mixed crystals are observed. Their appearance is accounted for by the uncovering of the Brillouin zone due to the disturbance of the periodicity of the crystal la...
Anharmonic line shift and linewidth of the Raman modes in GaS0.75Se0.25 layered crystals
Hasanlı, Nızamı (Wiley, 2002-11-01)
The frequencies and linewidths of five Raman-active modes in a GaS0.75Se0.25 layered crystal have been measured in the 10-300 K temperature range and in the 10-380 cm(-1) frequency region. We observed softening and broadening of the optical phonon lines with increasing temperature. The analysis of the experimental data showed that the temperature dependencies of frequencies and linewidths are well described by considering the contributions from thermal expansion and lattice anharmonicity. The purely anharmo...
BURLAKOV, VM; RYABOV, AP; YAKHEEV, MP; VINOGRADOV, EA; MELNIK, NN; Hasanlı, Nızamı (Wiley, 1989-06-01)
Low‐frequency Raman spectra of a TlInS2 single crystal in the vicinity of a ferroelectric phase transition are reported. In the ferroelectric phase a soft mode interacting with some rigid modes is observed. The temperature dependence of the soft mode frequency is found to be proportional to (Tc – T)1/2. An unusual behaviour of the rigid mode (ω = 20 cm−1) is observed. This fact is interpreted in terms of inherent lattice defects which cause nonhomogeneous broadening.
Citation Formats
M. IŞIK, N. Hasanlı, and F. KORKMAZ ÖZKAN, “Multiphonon absorption processes in layered structured TlGaS2, TlInS2 and TlGaSe2 single crystals,” PHYSICA B-CONDENSED MATTER, pp. 50–52, 2013, Accessed: 00, 2020. [Online]. Available: