p型Na掺杂各向异性ZnO的电子性质与热电输运性质

Electronic and Thermoelectrical Properties of p-Type Na Doped Anisotropic ZnO

采用密度泛函理论的第一性原理计算研究了p型Na掺杂各向异性ZnO的能带结构、光学性质、介电性质、总态密度和不同原子的分态密度,并系统分析了其热电输运性质。计算分析结果表明,p型Na掺杂ZnO为p型直接带隙半导体,其带隙增大到1.3eV,其对于光子的吸收限向低能量光子移动,体系费米能级附近的态密度大幅度提高,这主要是p态电子贡献的;在费米能级附近的导带和价带中都出现了新的能级,这些新的能级主要由Nas、Nap、Znp、Znd和Op电子形成,且他们之间存在着强耦合相互作用。Na掺杂ZnO的电输运性质具有各向异性;其价带和导带中的载流子有效质量均较大;载流子输运主要由Nas、Nap、Znp和Op电子完成。

The band structure,optical properties,dielectric property,density of states,partial density of states of the p-type Na doped ZnO have been investigated by the ab-initial calcultional method based on the density functional theory.The calculational and analyzing results show that the Na doped ZnO has approximately 1.3 eV direct band gap and it is ptype semiconductor,the absorption behavior is modified and the maximum absorbing peak move to the low optical photon,the density of state near Fermi level is increased and the pstate electrons forms these band states,there are newly formed bands within the valence bands and conducting bands near Fermi level that are fromed by the electons of Nas、Nap、Znp、Zndand the Opstate electrons.The elecrical property should be anisotropic for Na doped ZnO,the effec-tive mass within the valence bands and the conduction bands near Fermi level are high,the carrier conduction process is mainly accomplished by the Nas、Nap、Znpas well as the Opelectrons.