| Summary: | 碩士 === 中原大學 === 應用物理研究所 === 86 === In this letter, we report a systematic study accomplished with a series of Si-doped GaN epilayers with the carrier concentrations of 1016~1018 cm-3 in order tninvestigate the evolution of stress relaxation and yellow luminescence by Si incorporation. As the Si doping becomes higher, the bound exciton peaks are gradually shifted to lower energy due to relaxation of the thermal residual stress with the linear coefficient ofΔE/Δσc=39meV/GPa. The present results show that the photoluminescence intensity ratio of the yellow luminescence to edge emission gradually increase as the Si incorporation becomes heavier. We suggest that the Si doping in GaN epilayers induces overall defects and gives rise to stress relaxation during the cool-down process, and the yellow luminescence may be originated from a complex of VGa and the Si-induced defect,and no yellow luminescence has been observed in Mg-doped GaN epilayers.
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