Abstract Thin amorphous films of Cux(Ge30Se70)100-x (0 ≤ x ≤ 12 at. %) have been prepared onto glass substrates by the well-known thermal evaporation technique. The refractive index (n) of the studied films was obtained using only the transmission spectra, according to Swanepoel's method, within a wavelength range of 0.4–2.5 μm. Optical dispersion parameters such as the single oscillator energy (Eo) and dispersion energy (Ed) were estimated by applying the Wemple–DiDomenico model. Values of n were used via the Connell and Lewis equation to estimate the absorption coefficient (α), which in turn used to evaluate the values of both the extinction coefficient (k) and energy gap (Eg) of the films. It was found that Eg decreases from 2.21 to 1.86 eV with an increase of the Cu content from 0 to 12 at. %. Eg values were used to get the positions of the valence and conduction bands edges of the studied films theoretically. Urbach energy, which is correlated with the structural disorder, increases by increasing the Cu content. In addition, Eo decreases, whereas Ed increases by an increase in the Cu concentration. Using n and k, the optical dielectric constants, then the optical conductivity and the dissipation factor of the studied films have been calculated.

中文翻译：

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用于太阳能电池应用的三元 Cux(Ge30Se70)100-x 薄膜的光学常数

摘要 Cux(Ge30Se70)100-x (0 ≤ x ≤ 12 at. %) 的非晶薄膜已经通过众所周知的热蒸发技术制备在玻璃基板上。根据 Swanepoel 的方法，仅使用透射光谱在 0.4-2.5 μm 的波长范围内获得所研究薄膜的折射率 (n)。通过应用 Wemple-DiDomenico 模型估计光色散参数，例如单振荡器能量 (Eo) 和色散能量 (Ed)。通过 Connell 和 Lewis 方程使用 n 值来估计吸收系数 (α)，而吸收系数 (α) 又用于评估薄膜的消光系数 (k) 和能隙 (Eg) 的值。结果表明，随着 Cu 含量从 0 at 12 at 增加，Eg 从 2.21 eV 降低到 1.86 eV。%。Eg 值用于从理论上获得所研究薄膜的价带和导带边缘的位置。与结构无序相关的 Urbach 能量会随着 Cu 含量的增加而增加。此外，随着Cu浓度的增加，Eo减少，而Ed增加。使用 n 和 k，光学介电常数，然后计算了所研究薄膜的光导率和损耗因数。