Investigate the electronic and atomic structures of nonpolar a-plane GaN thin films

• Main Authors: Yi-Cheng Hsieh, 謝一正
• Other Authors: Jau-Wern Chiou
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/58516036018379534256

碩士 === 國立高雄大學 === 應用物理學系碩士班 === 101 === This study implemented a combination of atomic force microscope (AFM), X-ray diffraction pattern (XRD), Raman spectroscopy, and X-ay absorption near-edge structure (XANES) spectroscopy to investigate the relationship between the luminant properties, crystallography, and electronic structure of nonpolar a-GaN thin films. The nonpolar a-plane GaN thin films grown on γ-Al2O3 prepared by MOCVD (Metal-organic Chemical Vapor Deposition) method have the capabilities to overcome the QCSE (Quantum-confined Stark effect) existed in c-plane GaN thin films. The discrete V/III ratios and the thicknesses of the buffer layer are the variables during the sample preparation process. The XRD results show that the (11 0) orientation of the nonpolar a-GaN thin films depends on the thickness of the buffer layer is in agreement with the results of the Raman spectra. The XANES results suggest that the surface effect of the a-GaN thin films increased as the thickness of 1-st step a-GaN buffer layer increased. However, the N 2p-Ga 4sp antibonding coupling reduced with the decreased of the V/III ratio. Moreover, the amount of the N 2p-Ga 3d hybridization is not the factor to influence the electronic structure of nonpolar a-GaN thin films.