The optical and nanomechanical properties of Ga2Se3 single crystals and thin films were investigated using reflection, transmission, and nanoindentation measurements. The reflection spectrum recorded in the 525- to 1100-nm range was analyzed to get the band gap energy of the crystal structure, and derivative analysis of the spectrum resulted in band gap energy of 1.92 eV which was attributed to indirect transition. The band gap energy of thermally evaporated Ga2Se3 thin film was determined from the analysis of the transmittance spectrum. The absorption coefficient analysis presented the direct band gap energy as 2.60 eV. The refractive index was investigated in the transparent region using the Wemple–DiDomenico single-oscillator model. Nanoindentation measurements were carried out on the crystal and thin film structures of Ga2Se3. Nanohardness and elastic modulus of the Ga2Se3 single crystals and thin films were calculated following the Oliver–Pharr analysis method.

中文翻译：

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Ga2Se3 单晶和薄膜的光学和纳米力学性能

使用反射、透射和纳米压痕测量研究了 Ga2Se3 单晶和薄膜的光学和纳米机械性能。分析记录在 525 至 1100 nm 范围内的反射光谱以获得晶体结构的带隙能量，光谱的导数分析导致带隙能量为 1.92 eV，这归因于间接跃迁。热蒸发 Ga2Se3 薄膜的带隙能量由透射光谱分析确定。吸收系数分析表明直接带隙能量为 2.60 eV。使用 Wemple-DiDomenico 单振荡器模型研究透明区域的折射率。对 Ga2Se3 的晶体和薄膜结构进行了纳米压痕测量。