Structure and optical properties of Ge顥窯a顥窼 films deposited by thermal evaporation

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• 作者：Jing Fu ; ^{fujingsuny@163.com} ; Xiang Shen ; Guoxiang Wang ; Qiuhua Nie ; Fen Chen ; Jun Li ; Wei Zhang ; Shixun Dai ; Tiefeng Xu
• 关键词：Thin films ; Thermal evaporation technique ; Optical properties ; Local structure
• 刊名：Physica B
• 出版年：2012
• 期刊代码：53_09214526
• 类别：ph
• 出版时间：15 June, 2012
• 卷：407
• 期：12
• 页码：2340-2343
• 文件大小：259 K

摘要

Amorphous Ge顥窯a顥窼 thin films have been successfully deposited onto glass slides at room temperature by the thermal evaporation technique. The structural units of the films were studied using Raman spectroscopy. In addition to the basic structural units of GeS₄ tetrahedra, there are some S顥窼 and Ge顥窯e homopolar bonds which exist in the films. The increase in Ge atoms leads to the replacement of S顥窼 bonds by Ge顥窯e bonds, and the isolated Ge(Ga)S₄ tetrahedra units transform into corner-sharing or edge-sharing Ge(Ga)S₄ tetrahedra units in the films. The refractive index and optical band gap were derived from transmission spectra of films. The values of optical band gap decrease while the refractive indices increase with increasing Ge content. Composition dependence of optical band gap and refractive index has also been interpreted in terms of the variation in the structure of films based on Raman spectra.