| Summary: | 碩士 === 國立交通大學 === 電子物理系所 === 107 === In this thesis, the metal organic chemical vapor deposition system (MOCVD) is used to grow P-type gallium nitride on the Si (111) substrate by modulating the flow of Cp2Mg. Investigate its optical, structural, and electrical properties to explore the performance and growth mechanisms.
The dominant emission in the photoluminescence (PL) spectra is attributed to the donor-acceptor pair (DAP) recombination. As the flow rate of Cp2Mg increases, the luminescence mechanism of the sample will gradually change from conduction band to acceptor (eA) emission or DAP to deep donor-acceptor pair (DDAP) recombination, which results in a red shift in the emission energy. Raman spectroscopy indicates that the sample is mainly subjected to a compressive stress and shifts toward to the tensile stress as the flow rate increases.
In terms of structure investigation,the surface roughness increases with the increasing flow rate.The surface after annealing is also non-uniform, which is confirmed by energy dispersive spectroscopy (EDS) as the incorporation of magnesium atoms. The X-ray diffraction (XRD) rocking curve is measured to calculate the dislocation density, which is roughly positively correlated with the flow rate.
In terms of electrical properties, Hall measurement shows that the hole concentration increases with the flow rate up to 1.485×1018 cm-3.The Mg doping concentration was measured by the secondary ion spectrometry(SIMS) to calculate the hole activation rate as high as 2.06%, which might be due to the change in stress, dislocation density and the decrease in activation energy.
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