The authors in this article present the synthesis of good quality CuGaGeSe4 thin films of different thicknesses using electron beam deposition on well pre-cleaned glass substrates. X-ray diffraction patterns displayed the amorphous nature of as-prepared CuGaGeSe4 thin films. In addition, the elemental compositional analysis of these films was examined by the energy-dispersive X-ray spectroscopy technique, which showed that there is good matching between the selected and detected percentages. Transmittance and reflectance spectra of these CuGaGeSe4 samples were measured to experimentally determine the absorption coefficient and some related optical parameters. Optical band-gap energy values of samples were determined via Tauc’s Plots; they are arisen owing to the indirect allowed transition. They are decreased from 1.43 to 1.29 eV by increasing the film thickness from 250 to 445 nm. The skin depth, absorption index, and refractive index of CuGaGeSe4 thin films were also obtained and extensively studied. As well as, some optoelectrical parameters of these investigated films were discussed, like optical resistivity, optical mobility, optical conductivity, the lattice dielectric constant, and the ratio of the charge carrier concentrations to the effective mass (Nopt/m*). Along with, some nonlinear optical parameters of CuGaGeSe4 films were studied employing Miller’s formulas. The values of the dispersion energy, static refractive index, the static dielectric constant, the oscillator strength and others increase, while the oscillator energy and the relaxation time decrease as the film thickness increased. The obtained results showed that these CuGaGeSe4 film samples can be successfully used as absorption layers in thin-film solar cells.

中文翻译：

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薄膜厚度对电子束沉积合成的新型 CuGaGeSe4 薄膜光学性能和光电参数的影响

本文的作者介绍了使用电子束沉积在预先清洁过的玻璃基板上合成不同厚度的优质 CuGaGeSe4 薄膜。X 射线衍射图显示了所制备的 CuGaGeSe4 薄膜的非晶性质。此外，通过能量色散 X 射线光谱技术检查这些薄膜的元素组成分析，表明所选百分比和检测百分比之间存在良好的匹配。测量这些 CuGaGeSe4 样品的透射和反射光谱，以通过实验确定吸收系数和一些相关的光学参数。样品的光学带隙能量值通过 Tauc's Plots 确定；它们是由于允许的间接过渡而产生的。它们从 1.43 减少到 1。通过将薄膜厚度从 250 nm 增加到 445 nm，可以得到 29 eV。还获得并广泛研究了 CuGaGeSe4 薄膜的趋肤深度、吸收指数和折射率。此外，还讨论了这些研究薄膜的一些光电参数，如光电阻率、光迁移率、光导率、晶格介电常数以及电荷载流子浓度与有效质量的比率 (Nopt/m*)。同时，使用米勒公式研究了 CuGaGeSe4 薄膜的一些非线性光学参数。色散能、静态折射率、静态介电常数、振子强度等值增加，而振子能量和弛豫时间随着薄膜厚度的增加而减小。