Fizik Bilim Dalı Yayın Koleksiyonu

Exploring the linear and nonlinear optical behavior of (TlInS2)0.75(TlInSe2)0.25: Insights from ellipsometry measurements

Fri, 01 Sep 2023 00:00:00 GMT

Exploring the linear and nonlinear optical behavior of (TlInS2)0.75(TlInSe2)0.25: Insights from ellipsometry measurements Işık, M.; Güler, İpek; 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.

Characterization of linear and nonlinear optical properties of NaBi(WO4)2 crystal by spectroscopic ellipsometry

Thu, 01 Feb 2024 00:00:00 GMT

Characterization of linear and nonlinear optical properties of NaBi(WO4)2 crystal by spectroscopic ellipsometry Işık, M.; Güler, İpek; Gasanly, N. M. NaBi(WO4)2 compound has been a material of considerable attention in optoelectronic applications. The present research, in which we examined the linear and nonlinear optical properties of NaBi(WO4)2 crystal using the spectroscopic ellipsometry method, elucidates the optical behavior of the crystal in detail. Our work provides a sensitive approach to determine the spectral characteristic of the crystal. The spectral dependence of various optical parameters such as refractive index, extinction coefficient, dielectric function and absorption coefficient was reported in the range of 1.2-5.0 eV. Optical values such as bandgap energy, critical point energy, single oscillator parameters were obtained as a result of the analyses. In addition to linear optical properties, we also investigated the nonlinear optical behavior of NaBi(WO4)2 and shed new light on the potential applications of the crystal. Absorbance and photoluminescence spectra of the crystal were also reported to characterize optical, electronic and emission behavior of the compound. Our findings may form the basis for a number of technological applications such as optoelectronic devices, frequency conversion, and optical sensors. This research contributes to a better understanding of the optical properties of NaBi(WO4)2 crystal, highlighting the material's role in future optical and electronic technologies.

Thermoluminescence in gallium sesquisulfide single crystals: usual and unusual heating rate dependencies

Sun, 01 Jul 2018 00:00:00 GMT

Thermoluminescence in gallium sesquisulfide single crystals: usual and unusual heating rate dependencies Guler, I.; Isik, M.; Gasanova, L.; Mahammadov, A.; Gasanly, N. Thermoluminescence (TL) experiments were conducted for Ga2S3 crystals to obtain information about trapping parameters. TL measurements were performed from 10 to 300 K with varying heating rates in the range of 0.2–0.8 K/s. Two TL glow peaks centered at 44 K (peak A) and 91 K (peak B) were observed at heating rate of β = 0.5 K/s. For peak A, TL intensity decreased whereas that for peak B increased with elevating the heating rates that means anomalous heating rate occurred for peak B. TL glow curves were analyzed using initial rise method to find activation energies of traps. Distribution of trap centers was investigated using Tmax − Tstop method. Quasi-continuous distributions with increasing activation energies from 40 to 135 meV and 193 to 460 meV were attributed to trap centers A and B, respectively.

Investigation of the anomalous behavior of the linewidth (damping constant) for the Raman Ag modes in SrSnO3 ceramic

Sat, 01 Jan 2022 00:00:00 GMT

Investigation of the anomalous behavior of the linewidth (damping constant) for the Raman Ag modes in SrSnO3 ceramic Kiracı, Ali The anomalous behavior of the linewidth (damping constant) for the Raman Ag modes of 223 cm−1 and 260 cm−1 that contribute to the phase transition mechanism of SrSnO3 ceramic close to the phase transition temperatures of TC1= 650 K and TC2= 530 K, respectively, was calculated as function of temperature from the pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models below (T < TC) and above (T > TC) the phase transition temperatures of TC1 and TC2. For this calculation, the frequency shift of these modes were associated as the order parameter and disorder parameter below and above TC, respectively. Our results are in good agreement with the observed linewidth of these 223 cm−1 and 260 cm−1 Raman Ag modes. In addition, these two models (PS and EF) were used to deduce the values of the activation energy for SrSnO3 ceramic below and above the phase transition temperatures of TC1 and TC2.