大功率激光制备a-C和a-C∶H类金刚石膜的光学性能研究

采用大功率高重复频率准分子激光溅射热解石墨靶制备了类金刚石碳膜, 研究了实验条件对类金刚石膜光学性能的影响, 发现氢可以提高膜中sp3键的含量和膜的光学透过率. 在实验参数范围内, 膜的光学性能随着氢压的增加而提高. 根据类金刚石膜的反应沉积机理对上述结果进行了分析、解释.

Optical Properties of a-C and a-C: H Diamond-like Films Prepared by High Power Excimer Laser Ablation

The amorphous carbon films have many superior properties such as high hardness, high wear resistance, low coefficient of friction, etc., making them suitable for many applications so that many studies have focused on the synthesis and characterization of carbon coatings in the past years. The films can be prepared by different techniques, among them was pulsed laser deposition(PLD) which has attracted much attention mainly due to the good quality film it produces. In this work amorphous carbon(a-C) and a-C∶H films were deposited by high frequency and high power pulsed XeCl excimer laser ablation of pyrolytic graphite targets at room temperature. The effect of the laser power density and the pressure of hydrogen atmosphere on the optical properties of the films were studied by setting the laser peak power density on the target at 108, 109 and 1010 W/cm2, respectively, and the pressure of the hydrogen was 0, 2, 20 and 50 Pa while the laser density at 1010 W/cm2. Raman spectra as well as the UV and IR transparency were used for film analysis. The results indicate that the optical property of the films was improved with the increase of the laser power density and the hydrogen pressure, respectively. The reason was demonstrated according to the pulsed laser deposition mechanism.