2 results
Search Results
Now showing 1 - 2 of 2
Article Citation - WoS: 7Citation - Scopus: 7Exploring the Linear and Nonlinear Optical Behavior of (tlins2)0.75(tlinse2)0.25: Insights From Ellipsometry Measurements(Elsevier, 2023) Isik, M.; Guler, I.; Gasanly, N.The search for layered structured new semiconductor materials with remarkable optical properties has become a driving force, especially for materials science. Tl2In2S3Se [(TlInS2)0.75(TlInSe2)0.25], a fascinating compound, holds great promise for advanced photonic and optoelectronic applications. In the present study, the linear and nonlinear optical properties of Tl2In2S3Se layered single crystals were studied by ellipsometry measurements. The variation of refractive index, extinction coefficient, absorption coefficient and skin depth with energy were investigated. Applying the derivative analysis technique to the absorption spectrum, indirect bandgap was found as 2.19 eV. The refractive index data was analyzed considering single-effective-oscillator model. The lattice dielectric constant, plasma frequency, carrier density to the effective mass ratio and zero-frequency refractive index were found. Moreover, the change in optical conductivity with energy yielded to determine the direct bandgap as 2.40 eV. The optical parameters of nonlinear refractive index, first-and third-order nonlinear susceptibilities were also reported.Article Citation - WoS: 11Citation - Scopus: 11Ellipsometry Study of Interband Transitions in Tlgas2x< Mixed Crystals (0 ≤ x ≤ 1)(Elsevier, 2012) Isik, M.; Gasanly, N. M.In this paper, the spectroscopic ellipsometry measurements on TlGaS2xSe2(1 - x) mixed crystals (0 <= x <= 1) were carried out on the layer-plane (001) surfaces with light polarization E perpendicular to c* in the 1.2-6.2 eV spectral range at room temperature. The real and imaginary parts of the dielectric function, refractive index and extinction coefficient were calculated from ellipsometric data using the ambient-substrate optical model. The critical point energies in the above-band gap energy range have been obtained from the second derivative spectra of the dielectric function. Particularly for TlGaSe2 crystals, the determined critical point energies were assigned tentatively to interband transitions using the available electronic energy band structure. The effect of the isomorphic anion substitution (sulfur for selenium) on critical point energies in TlGaS2xSe2(1 - x) mixed crystals was established. (C) 2012 Elsevier B.V. All rights reserved.
