The phenomenon of band gap widening, attributed to quantum confinement resulting from films' thinning, is of significant interest in the photovoltaic field. Specifically, changes in CdTe and CdS band gaps are important in band engineering to facilitate devices coupling. Therefore, in this study, the sputtering technique is employed to deposit both materials with varying thicknesses within the 10–405 nm range. Structural and optical properties as functions of film thickness were assessed, and the band gap was determined through the Brus and absorption spectrum fitting (ASF) methods to compare it. Brus and ASF methods, demonstrated how the band gap changes with varying film thickness for both materials. However, a noticeable shift was observed between the methods in their respective curves. An explanation for this shift, and a new model correlating the reduction in film thickness with optical band gap widening is provided. This model constitutes the primary contribution of this paper.

中文翻译：

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纳米溅射 CdTe 和 CdS 薄膜的带隙分析

由于薄膜变薄导致的量子限制而导致的带隙展宽现象在光伏领域引起了人们的极大兴趣。具体来说，CdTe 和 CdS 带隙的变化对于能带工程中促进器件耦合非常重要。因此，在本研究中，采用溅射技术沉积两种厚度在 10-405 nm 范围内的材料。评估了作为薄膜厚度函数的结构和光学特性，并通过 Brus 和吸收光谱拟合 (ASF) 方法确定带隙并进行比较。Brus 和 ASF 方法演示了两种材料的带隙如何随着薄膜厚度的变化而变化。然而，在这些方法各自的曲线中观察到明显的变化。提供了对这种转变的解释，以及将薄膜厚度的减小与光学带隙加宽相关联的新模型。该模型构成了本文的主要贡献。