采用热蒸发法技术沉积Ge34Ga2S64非晶薄膜,并对薄膜样品在375℃热处理2h。通过分光光度计、表面轮廓仪和显微拉曼光谱仪测试热处理前后薄膜样品的透过曲线、薄膜厚度和拉曼结构。利用薄膜干涉曲线的波峰和波谷计算了薄膜的厚度和折射率,并根据Swanepoel方法以及Tauc公式分别计算了薄膜折射率色散曲线和光学带隙等参数。结果表明,Ge34Ga2S64非晶薄膜经热处理后发生热致漂白效应,大分子团簇以及Ge-Ge、S-S同极错键含量明显减少,网络结构无序性降低,从而引起薄膜的光学吸收边蓝移、折射率降低、表面粗糙度(Ra)降低0.515nm和光学带隙增大0.118eV。
Amorphous films of Ge34Ga2S64were deposited on quartz substrates by using thermal evaporation method.The optical parameters of as-deposited and annealed films are calculated using the Swanepoel method and Tauc law from the optical transmission spectra.After the heat treatment of as-deposited films at 375 ℃ for 2 h,the thermal-bleaching effects are observed,which are related to the reduction of clusters and fragments,as well as the density of homopolar bonds confirmed by the Raman spectra.As a result,the absorption spectra are blue shifted,the optical band gap of the studied films is increased by 0.118 eV,and the surface roughness is decreased by 0.515 nm.