Cai Shuxian, Liu Zhonghua, Zhong Ni, Liu Shengbei, Liu Xingfang
National Research Center of Engineering Technology for Utilization of Functional Ingredients from Botanicals, Hunan Agriculture University, Changsha 410128, China.
Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China.
Materials (Basel). 2015 Aug 26;8(9):5586-5596. doi: 10.3390/ma8095263.
The Si(0001) face and C(000-1) face dependences on growth pressure of epitaxial graphene (EG) grown on 4H-SiC substrates by ethene chemical vapor deposition (CVD) was studied using atomic force microscopy (AFM) and micro-Raman spectroscopy (μ-Raman). AFM revealed that EGs on Si-faced substrates had clear stepped morphologies due to surface step bunching. However, This EG formation did not occur on C-faced substrates. It was shown by μ-Raman that the properties of EG on both polar faces were different. EGs on Si-faced substrates were relatively thinner and more uniform than on C-faced substrates at low growth pressure. On the other hand, D band related defects always appeared in EGs on Si-faced substrates, but they did not appear in EG on C-faced substrate at an appropriate growth pressure. This was due to the μ-Raman covering the step edges when measurements were performed on Si-faced substrates. The results of this study are useful for optimized growth of EG on polar surfaces of SiC substrates.
利用原子力显微镜（AFM）和显微拉曼光谱（μ - 拉曼）研究了通过乙烯化学气相沉积（CVD）在4H - SiC衬底上生长的外延石墨烯（EG）的Si(0001)面和C(000 - 1)面与生长压力的关系。AFM显示，由于表面台阶聚集，Si面衬底上的EG具有清晰的台阶形态。然而，这种EG形成在C面衬底上并未发生。μ - 拉曼表明，两个极性面上的EG性质不同。在低生长压力下，Si面衬底上的EG比C面衬底上的相对更薄且更均匀。另一方面，与D带相关的缺陷总是出现在Si面衬底上的EG中，但在适当的生长压力下，它们在C面衬底上的EG中并不出现。这是因为在对Si面衬底进行测量时，μ - 拉曼覆盖了台阶边缘。本研究结果有助于优化EG在SiC衬底极性表面上的生长。
