Growth and Characterizations of GaN-related Materials

• Main Authors: Wen-Hsiung Lee, 李文雄
• Other Authors: Wei-Kuo Chen
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/36252625542838899931

博士 === 國立交通大學 === 電子物理系 === 91 === We have grown the hexagonal and cubic GaN by using our homemade atmospheric metalorganic vapor phase epitaxy system (AP-MOVPE). The characteristics of these samples were investigated by using X-ray measurements, Hall measurements, photoluminescence, and Raman scattering. The spatial correlation modal of Raman scattering was adopted to analyze the asymmetric broadening of Raman modes. At the beginning, we tried to optimize the growth parameters of undoped GaN on sapphire, such as, buffer layer thickness, growth temperature, V/III ratio, nitridation, N2/H2 carrier gas mixing ratio, etc. For the cubic GaN growth, we tried to grow GaN on GaAs (001) substrate at different temperature. We found co-existing of hexagonal and cubic phase in the samples. To investigate the As incorporation effect in GaN, we introduced the TBA (tertiarybutylarsnie) into the reactor when preparing GaN samples at different growth temperature or different flow rate. The lightly As-doped GaN grown at the temperature of 900oC~1000oC showed better quality than undoped GaN. At 700oC~800oC, we obtained GaAsxN1-x with As content of ~0.7%. For the study of As diffusion effect in GaN, we tried to anneal the GaN samples with thin GaAs interlayer. The intensity of characteristic green-line emission around 500 nm in the PL spectra increased with annealing temperature. However, the green emission disappeared because the annealing temperature of 1000 oC was too high.