摘要
用基于密度泛函理论平面波赝势法首先对六方AlN本征点缺陷(氮空位、铝空位、氮替代铝、铝替代氮、氮间隙、铝间隙)存在时的晶格结构进行优化,得到其稳定结构;然后通过各缺陷形成能的计算可得知其在生长过程中形成的难易程度;最后从态密度的角度对各种本征点缺陷引起的缺陷能级及电子占据情况进行了分析.发现除氮空位外其他本征缺陷在带隙中形成的能级都很深,要得到n型或p型AlN必须要引入外来杂质.计算得到的本征缺陷能级对于分析AlN的一些非带边辐射机理有重要帮助.
The change of atom configuration in hexagonal AlN, caused by native point defects （N and Al vacancies, N and Al antisites, N and Al interstitials）, are calculated firstly by plan-wave pseudopotential method with the generalized gradient approximation in the frame of density functional theory, and the most stable structure are obtained. Then the formation energy of each kind of native point defect is calculated, by which the possibilities of the six kinds of native defects to be formed during crystal growth are analyzed. Finally, the defect energy levels responding to every kind of native point defect and their electron occupancy are analyzed from the aspect of density of states. The results show that all the native defects form very deep energy levels in the band gap except N vacancy, and foreign impurities are needed to realize n-or p-type AlN. The values of defect energy levels obtained will be helpful in ascertaining the luminescence mechanism of some AlN non-band-edge emissions.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第9期5376-5381,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10474078)资助的课题.~~
关键词
六方AlN
形成能
缺陷能级
态密度
hexagonal AlN, formation energy, defect energy level, density of states
