衬底温度对电子束沉积ZnSe薄膜性能影响研究

Influence of Substrate Temperature on Properties of ZnSe Thin Films Deposited by Electron-beam Evaporation

为了研究衬底温度对硒化锌薄膜微观结构和光学特性的影响,采用电子束蒸发技术在K9玻璃基底上制备了单层的硒化锌薄膜。通过研究薄膜的X射线衍射谱、透射光谱特性、表面形貌及粗糙度,分析了不同衬底温度下薄膜微观晶体结构和光学特性的变化规律。实验结果表明:在20~200℃的衬底温度范围内制备的ZnSe薄膜均为具有(111)晶面择优取向的纳米晶薄膜,随着衬底温度升高,基片上原子获得的动能增加,导致薄膜的晶粒尺寸变大、内应力和位错密度降低;同样在不同衬底温度下,薄膜的光学特性也不尽相同,随着衬底温度的升高,折射率和消光系数减小、光学带隙增加、薄膜的表面粗糙度降低。分析表明折射率下降是薄膜中空隙部分所占比例增加所致,而消光系数的下降是薄膜结晶度提高,内部缺陷减少造成的。

In order to study the influence of substrate temperature on the microstructure and optical properties of ZnSe thin films,a single layer of ZnSe thin films was prepared on K9 glass substrate by electron beam evaporation.By studying the X-ray diffraction spectrum,transmission spectrum characteristics,surface morphology and roughness of the thin film,the variation rules of the microstructure and optical properties of the thin film under different substrate temperatures were analyzed.The experimental results show that the ZnSe films prepared in the range of substrate temperature from 20℃to200℃are all single crystal films with(111)crystallographic texture.With the increase of substrate temperature,the kinetic energy obtained by atoms on the substrate increases,resulting in the increase of grain size,internal strain and dislocation density of the films.The optical properties of thin films are also different at different substrate temperatures.With the increase of substrate temperature,the refractive index and extinction coefficient decrease,the optical band gap increases,and the surface roughness of thin films decreases.It is concluded that the decrease of refractive index is caused by the increase of the proportion of the pores in the film,and the decrease of extinction coefficient is caused by the increase of crystallinity and the reduction of internal defects.