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

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