The research work is devoted to study the influence of annealing temperature on the structural and optical properties of ZnSe thin films. The samples are prepared by a thermal evaporation technique and part of the as‐deposited films are annealed. X‐ray diffraction patterns and Raman spectra analysis reveal that the ZnSe thin films have cubic zinc‐blende crystal structure and the crystallinity increases as the annealing temperature increases. For the linear optical parameters, the absorption edge moves to shorter wavelengths with the increase of annealing temperature. Based on Swanepoel's method, the refractive index, film thickness, absorption coefficient and optical band gap are determined. The values of band gap are found to increase from 2.63 to 2.68 eV as the annealing temperature increases. By performing an open aperture Z‐scan technique with femtosecond pulses under 800 nm wavelength, all ZnSe samples show two‐photon absorption responses. It is found that the modulation depth and the two‐photon absorption coefficient decrease with increasing annealing temperature. Moreover, all samples exhibit better optical limiting responses at higher incident power intensities. These novel properties render this a promising material for traditional optoelectronic devices and optical limiters.

中文翻译：

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退火温度调制对ZnSe薄膜结构和光学性能的影响

研究工作致力于研究退火温度对ZnSe薄膜的结构和光学性能的影响。通过热蒸发技术制备样品，然后将部分沉积的薄膜退火。X射线衍射图谱和拉曼光谱分析表明ZnSe薄膜具有立方的闪锌矿晶体结构，并且随着退火温度的升高结晶度也随之增加。对于线性光学参数，随着退火温度的升高，吸收边移动到较短的波长。根据Swanepoel方法，确定折射率，膜厚，吸收系数和光学带隙。随着退火温度的升高，带隙的值从2.63 eV增加到2.68 eV。通过对波长在800 nm以下的飞秒脉冲执行开孔Z扫描技术，所有ZnSe样品均显示出双光子吸收响应。发现随着退火温度的升高，调制深度和双光子吸收系数降低。此外，所有样品在较高的入射功率强度下均表现出更好的光学极限响应。这些新颖的特性使它成为用于传统光电器件和光学限制器的有前途的材料。