氮空位在纳米GaN颗粒和InGaN/AlGaN双异质结中的聚集

摘要

Deficiency of nitrogen in nano GaN particles, synthesized by using dcarc plasma method, results in N vacancies. These vacancies aggregated further iallic gallium atoms on the surface of the particle were observed under the electron beam irradiation during the high resolution electron microscopy observation. Microscopic study has revealed that the modulated structure results from aggregation of nitrogenvacancies and has been supported by molecular mechanical simulations. The formation of voids, 50～100nm in diameters, within an InGaN/AlGaN double heterostructure grown by metal organic chemical vapor deposition on sapphire substrate has also been found by using transmission electron microscopy. The presence of voids results in a failure in electroluminescence.%直流放电等离子法制备纳米GaN颗粒中的氮缺乏可导致空位形成.在电子显微观察的电子辐照条件下,这些N 空位将进一步凝聚,形成一个a= 2 209nm,b= 3 826nm, c=1 037nm,α=β=γ=90°的调制结构.随着电子辐照剂量增加,纳米颗粒中心将出现空洞,同时使该区的金属镓离子迁移到颗粒的表面.电子显微分析及分子力学理论计算表明,这种新的调制结构系空位的有序排列所致.在此基础上,进一步研究了InGaN/AlGaN 的双异质结薄膜结构中直径约为50nm的空洞存在与发光失效的关系,讨论了N 空位的聚集与空洞形成的关系.