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采用等离子体增强化学气相沉积(PECVD)和电子束蒸发法在Si基GaN模板上先后淀积一层SiO2和Ni薄膜,接着在氮气中快速热退火(RTA)自组装生长Ni纳米点,最后以Ni纳米点为掩膜制备GaN纳米柱阵列,研究其制备条件的影响。扫描电镜(SEM)分析显示,随着Ni层厚度的减小、退火温度的降低和时间的延长,Ni纳米点的平均尺寸减小、密度增大。光致发光谱(PL)研究表明,GaN纳米柱比GaN模板的发光强度提高了约20倍,带边峰发生27 meV蓝移,这归因于GaN纳米柱具有较大的比表面积和张应力的部分弛豫。
A series of SiO2 and Ni thin films were successively deposited on Si-based GaN templates by plasma enhanced chemical vapor deposition (PECVD) and electron beam evaporation followed by rapid thermal annealing (RTA) in nitrogen to grow Ni nanodots. Finally, Ni nanodots as a mask for the preparation of GaN nano-column array to study the preparation conditions. Scanning electron microscopy (SEM) analysis showed that with the decrease of Ni layer thickness, the decrease of annealing temperature and the extension of time, the average size and the density of Ni nanodots decrease. Photoluminescence (PL) studies show that the luminescence intensity of GaN nanorods is about 20 times higher than that of GaN template, and the band edge peak shifts by 27 meV, which is attributed to the large specific surface area and tensile stress of GaN nanocolumns Partial relaxation.