高增透的类金刚石碳膜的红外吸收特性研究

Infrared Absorption Characterization of Diamond-Like Carbon Films

利用射频等离子体分解甲烷的技术在锗片上沉积了非晶结构的类金刚石碳膜。傅里叶红外光谱仪测量显示镀覆了类金刚石碳膜的锗片在红外范围内具有高增透作用 ,特别在 174 0～ 2 0 4 4cm-1其峰值透过率高达 99% ,在 94 5.7cm-1(10 .6 μm)处透过率为 94 .5%。利用实测的透过率曲线和改进的透过率公式 ,获得了该膜在 2 .5～ 12 μm的吸收系数 ,在 170 0～ 2 6 0 0 cm-1范围内的吸收系数接近于 0 ,在 10 .6 μm的吸收系数为 2 30 cm-1,膜主要由 sp3的 C- H键结构组成 。

Diamond- like carbon( DLC) i.e.amorphous carbon films were grown on germani- um ( Ge) substrates by rf- plasma decomposition of methane. Fourier transform infrared ( FTIR) spectroscopy measurement showed that the DLC films acted as the anti- reflect coat- ings of Ge substrates,especially,maxima of the transmission of DLC/ Ge/ DL C were above 99% from 1 740 cm- 1 to 2 0 44cm- 1 ,94.5 % at 945 .7cm- 1 ( 1 0 .6μm) . IR transmission spec- troscopy and improved transmission formula were used to calculate the absorption coefficient of DLC films from2 .5 μm to1 2 μm.The results indicated that the absorption coefficient of the films approached0 ranging from1 70 0 cm- 1 to2 6 0 0 cm- 1 and2 30 cm- 1 at945 .7cm- 1 . Thesp3C- H bonds were dominate in the DLC films.All the absorption peaks were well ex- plained by bonds.