Optical properties of TlGa(SxSe1-x) 2 layered mixed crystals (0=x=1): Absorption edge and photoluminescence study at T=10 K

Transmittance measurements of layered mixed crystals were performed in the 1.80-2.80 eV photon energy range at . Band-gap energies of the studied crystals were estimated by means of the derivative spectra of transmittance and photon energy dependence of absorption coefficient. The compositional dependence of direct band-gap energy at revealed that as sulphur (selenium) composition is increased (decreased) in the mixed crystals, the direct band-gap energy increases from 2.19 eV () to 2.67 eV (). Photoluminescence spectra of mixed crystals were investigated in the photon energy region of 2.00-3.10 eV at . The observed bands were assigned to the transitions of electrons from conduction band to the shallow acceptor levels in the band gap. The shift of the PL bands to higher energies with increasing sulphur content was revealed. In addition, the composition ratio of the mixed crystals was obtained from the energy-dispersive spectroscopy experiments.


Optical absorption and reflection studies of Tl4InGa3S8 layered single crystals
Goksen, K.; Hasanlı, Nızamı; Ozkan, H. (Institute of Physics, Polish Academy of Sciences, 2007-07-01)
The optical properties of Tl4InGa3S8 layered single crystals have been studied by means of transmission and reflection measurements in the wavelength region between 400 and 1100 nm. The analysis of the room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 2.40 and 2.61 eV, respectively. Transmission measurements carried out in the temperature range of 10-300 K revealed the rate of change of the indirect band gap with temperature as g...
Excitation intensity- and temperature-dependent photoluminescence in layered structured Tl2GaInSe2S2 crystals
Hasanlı, Nızamı (AIP Publishing, 2013-02-21)
Photoluminescence spectra of Tl2GaInSe2S2 layered crystals have been registered in the temperature range of 17-62 K and in the wavelength region of 525-690 nm. A broad visible photoluminescence band centered at 590 nm (2.10 eV) was observed at T 17 K. Variation of emission band has been studied as a function of laser excitation intensity in the 0.1-55.7 mW cm(-2) range. The analysis of the spectra reveals that the peak energy position changes with excitation intensity (blue shift). The radiative transitions...
Photovoltaic Effect and Space Charge Limited Current Analysis in TlGaTe2 Crystals
QASRAWI, ATEF FAYEZ HASAN; Yaseen, T. R.; Eghbariy, B.; Hasanlı, Nızamı (Institute of Physics, Polish Academy of Sciences, 2012-07-01)
Anisotropic space charge limited current density analysis and photovoltaic effect in TlGaTe2 single crystals has been investigated. It is shown that, above 330 K, the crystal exhibits intrinsic and extrinsic type of conductivity along (c-axis) and perpendicular (a-axis) to the crystal's axis, respectively. The current density (J) is found to be space charge limited. It is proportional to the square and three halves power of voltage (V) along the a- and c-axis, respectively. Along the a-axis and at sufficien...
Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station
Aguilar, M.; et. al. (American Physical Society (APS), 2016-08-26)
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49 x 10(5) antiproton events and 2.42 x 10(9) proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range similar to 60 to similar to 500 GV, the antiproton (p) over bar, proton p, and positron e(+) fluxes are found to have nearly identical ri...
Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer
Aguilar, M.; et. al. (American Physical Society (APS), 2020-05-29)
We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8 x 10(6) Ne, 2.2 x 10(6) Mg, and 1.6 x 10(6) Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harde...
Citation Formats
N. Hasanlı, “Optical properties of TlGa(SxSe1-x) 2 layered mixed crystals (0=x=1): Absorption edge and photoluminescence study at T=10 K,” PRAMANA-JOURNAL OF PHYSICS, pp. 0–0, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48040.