Abstract:

Since graphene was made by mechanical exfoliation in 2004,it has attracted great interest due to its unique properties. The growth of graphene directly on insulating substrates without catalyst has emerged as a trend for chemical vapor deposition (CVD)-graphene. This growth method offers an advantage in avoiding the post-growth transfer process. So far,many insulating substrates have been used for graphene growth by CVD,such as Si,sapphire,SiC,and other substrates. In this work,Si,sapphire and SiC substrate were chosen for graphene growth. The surface morphology,defects,crystal quality and electronics characteristic of the samples were characterized by atomic force microscopy (AFM),optic microscopy (OM),Raman spectroscopy,and Hall system. AFM and Raman results showed that 3C-SiC layer could be controlled by Si₃N₄ covered on Si substrate,and 2D-FWHM of material on Si substrate was between 70 cm^-1 and 90 cm^-1,that crystal quality was not as good as material by traditional method. Graphene was grown on a 5.08 cm sapphire substrate,the material surface morphology appeared more flat under the lower growth temperature,while the crystal quality was better under the higher temperature. The carrier mobility is above 1000 cm²·V^-1·s^-1 at room temperature. Compared to epitaxial graphene by Si sublimation,CVD-grown graphene on SiC substrate has a more flat surface morphology,lower defect,better crystal quality,and higher carrier mobility. The highest carrier mobility of CVD-grown graphene on SiC substrate is 4900 cm²·V^-1·s^-1 at room temperature.

Key words: graphene, insulating substrates, chemical vapor deposition, surface, morphology, electronics characteristic

摘要：

利用化学气相沉积法，在Si衬底、蓝宝石衬底和SiC衬底上生长石墨烯材料，研究石墨烯的表面形貌、缺陷、晶体质量和电学特性。原子力显微镜、光学显微镜和拉曼光谱测试表明，Si₃N₄覆盖层可以有效抑制3C-SiC缓冲层的形成；低温生长有利于保持材料表面的平整度，高温生长有利于提高材料的晶体质量。5.08 cm蓝宝石衬底上石墨烯材料，室温下非接触Hall测试迁移超过1000 cm²·V^-1·s^-1，方块电阻不均匀性为2.6%。相对于Si衬底和蓝宝石衬底，SiC衬底上生长石墨烯材料的表面形态学更好，缺陷更低，晶体质量和电学特性更好，迁移率最高为4900 cm²·V^-1·s^-1。

关键词: 石墨烯, 绝缘衬底, 化学气相沉积, 表面, 形态学, 电学特性