Mg-doped GaN layers prepared by metalorganic chemical vapor deposition were annealed at temperatures between 550 and 950℃. Room temperature （RT） Hall and photoluminescence （PL） spectroscopy measurements were performed on the as-grown and annealed samples. After annealing at 850℃, a high hole concentration of 8 × 10^17 cm^-3 and a resistivity of 0. 8lΩ·cm are obtained. Two dominant defect-related PL emission bands in GaN.. Mg are investigated; the blue band is centered at 2. 8eV （BL） and the ultraviolet emission band is around 3.27eV （UVL）. The relative intensity of BL to UVL increases after annealing at 550℃, but decreases when the annealing temperature is raised from 650 to 850℃, and finally increases sharply when the annealing temperature is raised to 950~C. The hole concentration increases with increased Mg doping, and decreases for higher Mg doping concentrations. These results indicate that the difficulties in achieving high hole concentration of 10^18cm^-3 appear to be related not only to hydrogen passivation, but also to self-compensation.
对采用MOCVD(metalorganic chemical vapor phase deposition)技术生长在GaN/Sapphire衬底上的InN薄膜进行了Hall、吸收谱以及低温光致发光(photoluminescence,PL)谱的测量和分析.Hall测量发现,样品的载流子浓度分布在1018～1019cm-3.在10K温度下进行PL测量,并对其线形进行分析,得到InN的带隙在0.7eV左右.综合Hall、吸收谱及PL谱的结果发现,吸收边以及PL谱的峰值能量都随载流子浓度的增加而蓝移.此外,我们还讨论了由吸收谱计算InN带隙的存在的不确定性.
