Chen Wang-Shou, Zhu Jia-Qi, Han Jie-Cai, Tian Gui, Tan Man-Lin
Center for Composite Materials, Harbin Institute of Technology, Harbin 150080, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Jan;29(1):268-72.
Nitrogenated tetrahedral amorphous carbon (ta-C : N) films were prepared on the polished C--Si substrates by introducing highly pure nitrogen gas into the cathode region and the depositing chamber synchronously using filtered cathodic vacuum arc (FCVA) technology. The nitrogen content in the films was controlled by changing the flow rate of nitrogen gas. The configuration of ta-C : N films was investigated by means of X-ray photoelectron spectroscopy (XPS) and visible Raman spectroscopy. It was shown that the nitrogen content in the films increased from 0.84 at% to 5.37 at% monotonously when the nitrogen flow rate was varied from 2 seem to 20 sccm. The peak position of C (1s) core level moved towards higher binding energy with the increase in nitrogen content. The shift of C (1s) peak position could be ascribed to the chemical bonding between carbon and nitrogen atoms even though more three-fold coordinated sp2 configuration as in graphite was formed when the films were doped with more nitrogen atoms. Additionally, the half width of C(1s) peak gradually was also broadened with increasing nitrogen content. In order to discover clearly the changing regularities of the microstructure of the films, the XPS C(1s) spectra and Raman spectra were deconvoluted using a Gaussian-Lorentzian mixed lineshape. It was shown that the tetrahedral hybridization component was still dominant even though the ratio of sp2/sp3 obtained from C(1s) spectra rose with the increase in nitrogen content. The Raman measurements demonstrated that the G peak position shifted towards higher frequency from 1,561 to 1,578 cm(-1) and the ratio of ID/IG also rose with the increase in nitrogen content. Both results indicated that the graphitizing tendency could occur with the increase in nitrogen content in the films.
通过使用过滤阴极真空电弧（FCVA）技术，将高纯氮气同步引入阴极区域和沉积室，在抛光的C-Si衬底上制备了含氮四面体非晶碳（ta-C:N）薄膜。通过改变氮气流量来控制薄膜中的氮含量。利用X射线光电子能谱（XPS）和可见拉曼光谱对ta-C:N薄膜的结构进行了研究。结果表明，当氮气流量从2 sccm变化到20 sccm时，薄膜中的氮含量从0.84原子百分比单调增加到5.37原子百分比。随着氮含量的增加，C（1s）芯能级的峰位向更高结合能移动。C（1s）峰位的移动可归因于碳原子与氮原子之间的化学键合，尽管当薄膜中掺杂更多氮原子时，会形成更多如石墨中那样的三配位sp2构型。此外，C（1s）峰的半高宽也随着氮含量的增加而逐渐变宽。为了清晰地发现薄膜微观结构的变化规律，使用高斯-洛伦兹混合线形对XPS C（1s）光谱和拉曼光谱进行了去卷积。结果表明，尽管从C（1s）光谱得到的sp2/sp3比值随着氮含量的增加而升高，但四面体杂化成分仍然占主导。拉曼测量表明，G峰位置从1561 cm-1向更高频率移动到1578 cm-1，并且ID/IG比值也随着氮含量的增加而升高。这两个结果都表明，随着薄膜中氮含量的增加，可能会出现石墨化趋势。
