Optical Characteristics of Thermally Evaporated Thin a-(Cu₂ZnGe)_50−xSe_50+x Films

Abstract

The optical characteristics of a-(Cu2ZnGe)50-xSe50+x, CZGSe, (0≤x≤20 at.wt.%) films were studied. The amorphous nature of the films was affirmed via X-ray diffractograms. Energy-dispersive X-ray spectroscopy confirmed matching between selected compositional element percentages and those measured for all films. Many optical properties and parameters of CZGSe films were studied using UV-Vis-INR spectroscopic transmission and reflection measurements. The envelope methods have been successfully applied on the measured transmission spectra according to the Swanepoel technique, along with reflection spectra in accordance with the Minkov method. Obtained results based on the Swanepoel analysis are in excellent agreement with those inferred from the Minkov method. A clear blueshift of the absorption edge was observed from 854 to 720 nm, in accordance with the increasing optical bandgap energy values from 1.456 to 1.722 eV, as Se-content increases from 50 to 70 at.wt.%. The electronic transitions of (Cu2ZnGe)50-xSe50+x films arose from allowed indirect transitions. The observed energy gap increase was interpreted according to the Mott and Davies model. The absorption coefficient values have been estimated and are found to be larger than10-4cm-1. All discussed parameters strongly depend on the Se-concentration. The bonding strength between the elements of samples strongly affects the optical properties.

Optical and dispersion parameters of Ge-Zn-Se glassy films for VIS and FTIR Applications

“…x at% ρ V m Pd 10 Furthermore, the decreased values of (n) due to Se additions may be attributed to the polarizability decrement [40], where Se atoms has a smaller size (atomic radius , ar =115 pm) than Ge (ar =125 pm) and Zn (ar =135 pm) atoms [41]. Similar results have been observed in the literature for Se-based thin films [40,[42][43][44]. The extent of electronic responses to the electromagnetic field applications in the electronic clouds is defined as the electronic polarizability, ( el a ) of this material.…”

Synthesis, Structural, Optical and Optoelectrical Properties of the Chemically Deposited Cu2BaGeS4 Thin Films

“…As the sample thickness rose, the magnitudes of ω p also diminished. The relaxation time τ for the innovative Cu 2 BaGeS 4 samples was assessed according to the below relationship: 41 Furthermore, For assessing the optical resistivity and optical mobility of the Cu 2 BaGeS 4 samples, the subsequent equations were utilized: 42,43 These results reveal good regularity with the other published articles. 44 Further, the magnitudes of the n and α of the novel Cu 2 BaGeS 4 samples were utilized to compute the values of the electrical conductivity (σ e ) and the optical conductivity (σ opt ) according to the below formulas: 45,46…”

“…Figure 8b establishes the alteration of the ε 2 on the λ 3 for the Cu 2 BaGeS 4 samples. The thickness growth of the innovative Cu 2 BaGeS 4 films produce a reduction in the τ of the Cu 2 BaGeS 4 samples.Furthermore, For assessing the optical resistivity and optical mobility of the Cu 2 BaGeS 4 samples, the subsequent equations were utilized:42,43 …”

Time-dependent laser irradiation-induced kinetics of changes in linear–nonlinear optical properties of Bi15In20Se65 thin films for IR applications

“…30 Thus, a region corresponding to the high absorption value where α ≥ 10 4 cm −1 is known as the Tauc regime, which is used for the determination of the E g of the material. According to Tauc's relation, 38,39 (αhv…”