Synchrotron Radiation X-ray Absorption and Related Studies on CdS, ZnO and Ga2O3

• Main Authors: Chih-Cheng Wei, 魏志丞
• Other Authors: Zhe-Chuan Feng
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/83401250700508831180

碩士 === 國立臺灣大學 === 光電工程學研究所 === 98 === This thesis concerns with the studies on the optical and electrical properties on wide band gap materials of semiconductors. X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), Raman scattering (RS), optical transmission (OT), X-ray diffraction (XRD) and Photoluminescence (PL) are carried out to study the physical properties of CdS, Ga2O3, ZnO and GaN thin films. Many peculiar phenomena have been observed, which are very useful for the understanding as well as application of various wide band gap materials. In chapter 3, the optical properties of CdS on SnO2 coated glass were studied by multi-techniques, including Raman scattering, X-ray diffraction, Photoluminescence and optical transmittance. Otherwise, X-ray absorption provide us plenty information to figure out the crystal structure and electrical configuration. The results also show annealing procedures indeed improve thin films quality. In chapter 4, magnetic element Cr doped ZnO grown on Silicon under different sputtering temperatures and the comparison pair of Cr doped ZnO on different substrates were involved in this studied. From Raman spectra, it was found with increasing sputtering temperature to 600℃, additional modes (AMs) enhanced strongly, which is related to defect-induced modes. Moreover, the emission band gap appears at 3.22 eV. Apparently, the deposited of Cr under high temperatures can improve the emission efficiency near excitation edge. Chapter 5 was focused on optical transmittance and Raman studies on Ga2O3 grown on sapphire substrate, which the growth temperatures are distinct. We use Gaussian function to accomplish optical transmittance fitting and Lorentzain for Raman peaks fitting. Finally, two parts of GaN thin films analysis were shown in chapter 6. The first pair was rare earth (RE) element Gd doped GaN grown on c-sapphire, the section including Raman scattering and PL experiments. The second part was based on Yu-Li, Wu’s work, the strains of GaN on Si was studied by combining Raman shift and EXAFS.