We report the temperature-dependent phonon modes and interband electronic transitions of InSe films on SiO₂/Si substrates prepared by pulsed laser deposition. The microstructure results proved the ε phase structure and monochalcogenide phase composition with well-defined hexagonal InSe sheets. The temperature effects on lattice vibrations were discovered by Raman spectra from 123 K to 423 K. The frequency and full width at half maximum of the ${\mathrm{A}}_{2g}^1$(LO) mode show a strong nonlinearity with the temperature. The energy band structure and electron–phonon interaction were studied by temperature-dependent spectroscopic ellipsometry with the aid of the Tauc–Lorentz model. It was found that five electronic transitions around 1.33, 1.61, 2.53, 3.73, and 4.64 eV generally show a redshift trend with the temperature. The present results can provide a valuable reference for future optoelectronic applications of InSe films.

中文翻译：

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脉冲激光沉积产生的ε-InSe薄膜的温度依赖声子模式和带间电子跃迁演化

我们报告了由脉冲激光沉积制备的SiO ₂ / Si衬底上的InSe薄膜的温度依赖性声子模式和带间电子跃迁。微观结构结果证明了六方InSe片的ε相结构和一硫属元素化物相组成。温度对晶格振动的影响是通过拉曼光谱从123 K到423 K发现的。${\mathrm{一种}}_{2G}^{\mathrm{1个}}$（LO）模式显示出随温度的强烈非线性。借助Tauc-Lorentz模型，通过依赖温度的椭圆光谱法研究了能带结构和电子-声子相互作用。发现在1.33、1.61、2.53、3.73和4.64 eV附近的五个电子跃迁通常随温度显示红移趋势。本研究结果可为今后InSe薄膜的光电应用提供有价值的参考。