Optical constants of Tl4Ga3InSe8 layered single crystals

Goksen, K.
Hasanlı, Nızamı
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 is gamma = -4.1 X 10(-4) eV/K. The absolute zero value of the band gap energy was obtained as E-gi(0) = 2.03 eV. The dispersion of the refractive index is discussed in terms of the Wemple-DiDomenico single-effective-oscillator model. The refractive index dispersion parameters: oscillator energy, dispersion energy, oscillator strength and zero-frequency refractive index were found to be 4. 10 eV, 23.17 eV, 6.21 X 10(13)m(-2) and 2.58, respectively. From X-ray powder diffraction study, the parameters of monoclinic unit cell were determined.


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...
Multiphonon absorption processes in layered structured TlGaS2, TlInS2 and TlGaSe2 single crystals
IŞIK, MEHMET; Hasanlı, Nızamı; KORKMAZ ÖZKAN, FİLİZ (Elsevier BV, 2013-07-15)
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 silver and copper indium ternary sulfides from infrared reflectivity measurements
Hasanlı, Nızamı (Elsevier BV, 2016-03-01)
Infrared reflection spectra are obtained in the frequency range of 50-2000 cm(-1) for AgIn5S8 and CuIn5S8 single crystals grown by Bridgman method. All four infrared-active modes are detected, which are in full agreement with the prediction of group-theoretical analysis. Spectral dependence of optical parameters; real and imaginary parts of the dielectric function, the function of energy losses, refractive index, absorption index and absorption coefficient were calculated from reflectivity experiments. The ...
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...
Optical properties of (Ga2Se3)(0.)(75) - (Ga2S3)(0.)(25) single crystals by spectroscopic ellipsometry
Işık, Mehmet; Hasanlı, Nızamı; Gasanova, L. (Elsevier BV, 2019-05-01)
Structural and optical properties of 75 mol % Ga2Se3 - 25 mol % Ga2S3 system of single crystals were investigated by experimental techniques of x-ray diffraction (XRD), energy dispersive spectroscopy, Raman spectroscopy and ellipsometry. XRD pattern indicated that the studied compound has crystalline nature with cubic structure. Vibrational modes in the crystal were revealed using Raman spectroscopy experiments in the 90-450 cm(-1) frequency range and nine modes were observed in the spectrum. Ellipsometry m...
Citation Formats
K. Goksen and N. Hasanlı, “Optical constants of Tl4Ga3InSe8 layered single crystals,” PHYSICA B-CONDENSED MATTER, pp. 266–272, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39512.