The Research Of Growth Mechanism And Characterization Of Ga N With Graphene Interlayer By HVPE

Since graphene was discovered in 2004, researchers have taken more and more attentions to it. Gallium nitride(Ga N), as the representative of the third generation semiconductor materials, has been widely used because of its excellent optical properties. This thesis mainly studies the growth behavior of Ga N on graphene, including Chemical Vapor Deposition(CVD) growth of graphene and Hydride Vapor Phase Epitaxy(HVPE) method for Ga N growth. Electron microscope, X-ray diffraction(XRD), Raman spectroscopy and other characterization methods were adopted to characterize the morphology of graphene, Ga N films and the dislocation of Ga N materials. Low defect density(108cm-2order of magnitude) Ga N thin films were obtained by using optimized parameters. This thesis was mainly divided into the following sections:Chapter 1 introduces the background of the topic. We have reviewed the discovery of graphene and summarized the basic structure, properties and preparation methods of graphene, introduces the gallium nitride crystal structure, growth method and dislocation type, and introduces the growth progress of gallium nitride thin film on graphene. And finally is the arrangement of this paper.Chapter 2 introduces the main technical methods and instruments for characterization of graphene and Ga N films on graphene, including: Optical Microscope(OM), Scanning Electron Microscope(SEM), Transmission Electron microscopy(TEM), Raman spectroscopy(RS), Atomic Force microscopy(AFM) and X-ray Diffraction(XRD).Chapter 3 introduces growth of graphene by using CVD and epitaxy of Ga N on graphene by HVPE, and introduces several different ways to transfer graphene on target substrates. Graphene and Ga N was tested and analyzed. After growth of Ga N films on graphene. It shows that the threading dislocation density is at the order of magnitude of 108 cm-2 and it is consistent with the results of CL. Moreover, the surface morphology of the Ga N films was also investigated by using AFM and SEM. After growth of Ga N, The signal of G peak and 2D peak is detected by Raman and existence of graphene was evidenced.Chapter 4analyzes the types and distribution of Ga N dislocation, the dislocation in the substrate are also analyzed as a comparison. The effect of graphene on Ga N growth behavior, together with stress state were analyzed in the text.