α-C∶H膜化学结构对光学性能的影响

Influence of chemical structure of α-C∶H films on optics property

选用体积分数为99.9999%的H2及反式-2-丁烯(T2B)为工作气体,利用低压等离子体增强化学气相沉积法制备了α-C∶H薄膜。利用傅里叶变换红外光谱仪和X射线光电子能谱对薄膜化学键和电子结构进行分析,并结合高斯分峰拟合分析了薄膜中sp3/sp2杂化键比值和sp3C杂化键分数。结果表明:薄膜中氢含量较高,主要以sp3C—H形式存在;工作气压越高,制备的薄膜中C=C键含量越少,薄膜中sp3/sp2杂化键比值和sp3C杂化键分数增加,薄膜稳定性提高。应用UV-VIS光谱仪,获得了波长在400～1000nm范围内薄膜的光吸收特性,结果显示:α-C∶H薄膜透过率可达98%。光学常数公式计算得到工作压强为4～14Pa时光学带隙在2.66～2.76之间,并均随着工作气压的升高而增大。结果表明,随工作气压的升高,薄膜内sp3键减小,从而促使透过率、光学带隙增大。

α-C ： H thin films were deposited by low-pressure plasma chemical vapor deposition（LPPCVD） with H2 （99. 999 9%） and Trans-2-butene as source gases. The chemical bonds and electronic structure are analyzed by using FTIR and XPS. The ratio of sp^3/sp^2 and the percentage of sp^3 C are also analyzed by using the fitting of Gaussian peak fitting. The results show that the chemical structure and composition of the films change with the pressure, and this films mainly contain sp^3C-H bond, which have low pressure and possess less C= C bonds. When the pressure increases, the sp^3/sp^2 hybrid ratios and the percentage of spa bonds increase. The optical properties of α-C ： H films are investigated by UV-VIS spectrum in the range of 400-1 100 nm. The transmission ratios can reach 98% in the visible light range and the optical band gap ranges from 2.66 to 2.76. The sp^3 C content of the films increases and the C=C content decreases when the pressure increases, the optical band gap has a close relationship with the content of the sp^3C key, and the more the sp^3C content is, the bigger the optical band gap will be.