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）.
出处
《计算物理》
CSCD
北大核心
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
