Zn空位对Al-P共掺杂ZnO电子结构影响的第一性原理计算  

Effects of Zinc Vacancies on Electronic Structure of Al-P Co-doped ZnO:First-principles Calculations

作　　者：李磊磊 李维学[2,1] 戴剑锋[2,1] 王青[1] 

机构地区：[1]兰州理工大学理学院,兰州730050 [2]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050

出　　处：《计算物理》2017年第6期713-721,共9页Chinese Journal of Computational Physics

基　　金：国家自然科学基金(50873047);甘肃省科技计划(1010RJZA045)资助项目

摘　　要：采用第一性原理平面波赝势法计算ZnO(Al,P)体系的晶格参数和电子结构,重点分析Zn空位对体系晶体结构、形成能、态密度的影响.计算结果表明:Al和P共掺杂过程中,Al_(Zn)-P_(Zn)有更低的形成能,能带分析呈现n型.并随着Zn空位浓度的增大使得掺杂后的晶胞体积减小,晶格常数c先增大后减小.存在Zn空位的掺杂体系形成能比Al_(Zn)-PO掺杂体系低,体系较稳定.能带分析呈现p型趋势.Al和P以1∶2的比例掺杂时,体系的形成能降低,体系更稳定;同时,比较1个VZn和2个VZn的Al_(Zn)-P_(Zn)共掺杂体系的能带结构发现,随着Zn空位浓度增大,带隙增大,体系p型化特征增强.Al_(Zn)-2P_(Zn)共掺杂体系带隙减小为0.56 eV,更有利于提高其导电性质.然而出现2VZn后,带隙增大为0.73 eV,小于本征ZnO带隙,p型化程度更强烈;此外态密度分析表明2VZn的Al_(Zn)-2P_(Zn)共掺杂使得态密度更加分散,更多的电子穿过费米能级使得p型化更明显.因此,将Al/P按1∶2的比例共掺且Zn空位增至2个时,可以获得导电性能更好的p型ZnO.With pseudo-potential plane-wave based on density functional theory（DFT）,effects of zinc vacancies on ZnO lattice parameters and electronic structure of Al-P co-doped were studied.Formation energy,density of states are analysed.It shows that Al（Zn）P（Zn）has the lowest formation energy and presents n-type in the process of co-doping.Presence of zinc vacancies make cell volume decrease,and lattice constant c increase and decreases as concentration of zinc vacancies increase.According to formation energy of codoping,formation of zinc vacancies system is more stable than Al（Zn）-PO.System with Al and P ratio of 1∶2 co-doping can reduce formation energy and become more stable.With comparisons of band structure of V（Zn） and 2 V（Zn）,it is found that band gap increased with zinc vacancies increasing,which makes p-type ZnO more obvious and enhances conductivity of Al（Zn）-2 P（Zn） co-doping systems.However,for Al（Zn）-2 P（Zn） co-doping of 2 V（Zn）,it shows great superiority of p-type.According to state density analysis,Al（Zn）-2 P（Zn） of 2 V（Zn） makes the state density more diffuse,and go through the Fermi level,which leads to formation of obvious p-type.As a result,better p-type ZnO can be obtained by controlling Al/P in proportion of 1∶2 co-doing with zinc vacancy to 2 V（Zn）.

关 键 词：Al-P共掺杂 第一性原理 Zn空位 电子结构 

分 类 号：O474[理学—半导体物理]