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采用直流热阴极等离子体化学气相沉积(PCVD)技术,在CH4:H2中加入N2改变等离子体能量分布状态,提高二次形核比例,制备纳米金刚石膜。在CH4:H2气体中,在不同压力和温度下,改变通入N2的比例,分析直流热阴极等离子体放电下N2对金刚石膜生长的影响。采用拉曼光谱仪、扫描电镜(SEM)和X射线衍射分析仪(XRD)对样品进行了表征,结果表明,直流热阴极PCVD系统中,CH4:N2:H2气氛下,N2流量小于气体总流量的50%时,在6×103 Pa、850℃条件下,制备的金刚石膜样品的晶粒小于100nm、金刚石1332 cm-1特征峰展宽且强度较高、金刚石的XRD衍射峰强度也较高,具备纳米金刚石膜的基本特征。因此,利用直流热阴极PCVD方法,在较低温度和气压下,CH4:H2中加入少量N2,可以制备出纳米金刚石膜。
DC hot cathode plasma chemical vapor deposition (PCVD) technique was used to add N2 to CH4: H2 to change the plasma energy distribution and increase the secondary nucleation ratio to prepare nano-diamond films. In CH4: H2 gas, under different pressures and temperatures, the proportion of N2 was changed to analyze the effect of N2 on the growth of diamond films under DC hot cathode plasma discharge. The samples were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the N2 flow rate in CH4: N2: H2 atmosphere is less than the total gas flow in DC hot cathode PCVD system 50%, the grain size of the prepared diamond film is less than 100 nm at 6 × 103 Pa and 850 ℃, the characteristic peak of 1332 cm-1 of diamond is widened and the strength is high, and the XRD diffraction peak intensity of diamond is also high The basic characteristics of nano-diamond film. Therefore, the DC hot cathode PCVD method at a lower temperature and pressure, CH4: H2 in a small amount of N2, can be prepared nano-diamond film.