Anisotropic electrical and dispersive optical parameters in InS layered crystals

Hasanlı, Nızamı
The anisotropy effect on the current transport mechanism and on the dispersive optical parameters of indium monosulfide crystals has been studied by means of electrical conductivity and polarized reflectance measurements along the a-axis and the b-axis, respectively. The temperature-dependent electrical conductivity analysis in the range 10-350 K for the a-axis and in the range 30-350 K for the b-axis revealed the domination of the thermionic emission of charge carriers and the domination of variable range hopping above and below 100 K, respectively. At high temperatures (T > 100 K) the conductivity anisotropy, s, decreased sharply with decreasing temperature following the law s proportional to exp(-E(s)/kT). The anisotropy activation energy, E(s), was found to be 330 and 17 meV above and below 220 K, respectively. Below 100 K, the conductivity anisotropy is invariant with temperature. in that region, the calculated hopping parameters are altered significantly by the conductivity anisotropy. The optical reflectivity analysis in the wavelength range 250-650 nm revealed a clear anisotropy effect on the dispersive optical parameters. In particular, the static refractive index, static dielectric constant, lattice dielectric constant, dispersion energy and oscillator energy exhibited values of 2.89, 8.39, 19.7, 30.02 eV and 4.06 eV, and values of 2.76, 7.64, 25.9, 22.26 eV and 3.35 eV for light polarized along the a-axis and the b-axis, respectively.


Composition-tuned refractive index and oscillator parameters in TlGaxIn1-xS2 layered mixed crystals (0 <= x <= 1)
Hasanlı, Nızamı (Elsevier BV, 2010-09-01)
The optical properties of TlGaxIn1-xS2 mixed crystals have been studied through transmission and reflection measurements in the wavelength range 400-1100 nm. These measurements allowed determination of the spectral dependence of the refractive index for all compositions of the mixed crystals studied. The dispersion of the refractive index is discussed in terms of the Wemple-DiDomenico single-effective-oscillator model. The compositional dependences of the refractive index dispersion parameters (oscillator e...
Energy band gap and oscillator parameters of Ga4Se3S single crystals
Qasrawi, A. F.; Hasanlı, Nızamı (Elsevier BV, 2007-06-01)
The optical properties of the Bridgman method grown Ga4Se3S crystals have been investigated by means of room temperature, transmittance and reflectance spectral analysis. The optical data have revealed an indirect allowed transition band gap of 2.08 eV. The room temperature refractive index, which was calculated from the reflectance and transmittance data, allowed the identification of the dispersion and oscillator energies, static dielectric constant and static refractive index as 21.08 and 3.85 eV, 6.48 a...
Dependence of the photoluminescence of Tl2InGaS4 layered crystal on temperature and excitation intensity
Hasanlı, Nızamı; Gurlu, O; Aydinli, A; Yilmaz, I (Elsevier BV, 1998-01-01)
The emission band spectra of Tl2InGaS4 layered crystals were investigated in the 10-120 K temperature range and in the 540-860 nm wavelength range using photoluminescence (PL). The peak energy position of the emission band is located at 1.754 eV (707 nm) at 10 K. The emission band has a half-width of 0.28 eV and an asymmetric Gaussian lineshape. The increase of the half-width of the emission band, the blue shift of the emission band peak energy and the quenching of the PL with increasing temperature is expl...
Temperature-tuned band gap energy and oscillator parameters of Tl2InGaSe4 semiconducting layered single crystals
Hasanlı, Nızamı (Wiley, 2009-03-01)
The optical properties of Tl2InGaSe4 layered single crystals have been studied through the transmission and reflection measurements in the wavelength range of 500-1100 nm. The analysis of room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 1.86 and 2.05 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...
Nonlinear optical rectification in asymmetrical semiparabolic quantum wells
Karabulut, I; Safak, H; Tomak, Mehmet (Elsevier BV, 2005-09-01)
The optical rectification in a semiparabolic quantum well is theoretically investigated. The electronic states in a semiparabolic quantum well are calculated exactly, within the envelope function and the displaced harmonic oscillator approach. The nonlinearity resulting from the asymmetry of the confining potential is studied in the lowest order. The numerical results for the typical AlxGa1-xAs/GaAs material show that the large optical rectification coefficient decreases with increasing confining potential ...
Citation Formats
A. F. H. QASRAWI and N. Hasanlı, “Anisotropic electrical and dispersive optical parameters in InS layered crystals,” SOLID STATE COMMUNICATIONS, pp. 325–328, 2010, Accessed: 00, 2020. [Online]. Available: