(Al,Ga,In)和N择优位向共掺对ZnO光电性能影响的研究

Nowadays, although the study of（Al,Ga,In）and N co-doped effect on the photoelectric function of ZnO is relatively common, but all of（Al,Ga,In）and N co-doped ZnO are random doping, the preferential locality doping using the unpolarity structure of ZnO has not considered so for. Based on the density functional theory using first-principles plate-wave uitrasoft pseudopotential method, the supercells of un-doped and the preferential locality of (Al,Ga,In) and N co-doped ZnO have been set up respectively, the geometry optimizations, band structures, density of states, population, electron density difference and optical properties of these supercells also have been calculated. The effect on the systemic stability have been studied under the different doping concentration proportion of preferential locality, an expected ideal result of a more stable ZnO construction can be obtained under a certain doping concentration proportion. The effect on the conductivity of ZnO have been studied under the some doping concentration proportion and preferential locality, a heavier hole concentration of, lower effective mass, and better mobility and conductivity of hole can be obtained, we can select ideal, stable and low-resistance p-type ZnO semiconductor function materials by horizontal comparison. At the same time, the effect on the optical properties of ZnO also have been researched, an expected ideal result of low-absorption spectrum, low reflection spectrum intensity and high transmitted intensity can be got, we can select stable and high transmitted intensity p-type ZnO optical function materials by horizontal comparison. These results provide a theory guidance for the future experimental preparation of new p-type ZnO photoelectric function materials. The change rule of forbidden band regulation have been reasonably explained by the organic combination of the crystal field theory, chemical bond theory and energy band theory, this develops and improves the shortage of the donor-acceptor co-doped theory.

目前（Al,Ga,In）和N共掺对ZnO光电性能影响的研究比较普遍，但是（Al,Ga,In）和N在ZnO中均是随机共掺，目前还没有利用ZnO的单极性结构进行择优位向掺杂。本研究采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法，研究ZnO、（Al,Ga,In）和N择优位向共掺ZnO超胞模型，分别对模型进行结构优化、能带分布、态密度分布、集居数、差分电荷密度分布和光学性质的计算，在不同配比浓度择优位向掺杂的条件下，研究掺杂体系ZnO的稳定性，预期得出某一个配比浓度下，ZnO结构均较稳定的结果。在此基础上，研究掺杂体系ZnO的导电性能和光学性质。横向比较，预期得出稳定低阻的p型ZnO半导体功能材料和稳定性高、透射强的p型ZnO光学功能材料，为制备新型p型ZnO光电功能材料提供理论指导。将晶体场理论、化学键理论和能带论有机结合，合理解释禁带变化的规律，从而完善和发展施主-受主共掺理论。

本项目采用密度泛函理论框架下的第一性原理平面波超软赝势方法，第一，发现了在择优位向(Al, Ga, In)和N分别共掺不同配比掺杂浓度的条件下，掺杂体系ZnO均较稳定的配比浓度1: 2(Al/Ga/In:2N)。在此基础上，研究了掺杂体系ZnO p型化的导电性能，横向比较，发现了重掺杂的条件下，择优位向共掺后，同类择优位向共掺的体系中，沿c轴方向成键体系的电导率大于垂直于c轴方向成键体系的电导率。不同类沿c轴方向成键共掺的体系中, In-2N沿c轴方向成键共掺对ZnO的电导率最强，电离能最小，Bohr半径最大，In-2N沿c轴方向成键共掺对ZnO p型导电更有利。在择优位向(Al, Ga, In)和N分别共掺对ZnO光学性质的影响中，三种掺杂体系带隙均变窄，吸收光谱均红移。发现了在不同掺杂方式，相同浓度共掺In-2N或Ga-2N的条件下，In-N或Ga-N沿c轴取向成键共掺与垂直于c轴取向成键共掺体系相比较，沿c轴取向成键共掺体系最小光学带隙越变窄，吸收光谱红移越显著。这为设计和制备新型p型ZnO光电功能材料提供了有价值的可靠数据和结论。同时，完善和发展了施主-受主共掺理论。第二，本项目采用基于自旋密度泛函理论框架下的广义梯度近似(GGA)平面波超软赝势+U的方法，用第一性原理研究了(Li, Al, Ga)分别掺杂和点空位在ZnO中的稀磁半导体的磁性和机理影响，首次发现(Li, Al, Ga)分别掺杂和点空位在ZnO中，Li/Al/Ga替换Zn和Zn空位共存在ZnO中，能够实现长程有序铁磁性的特点，同时，发现掺杂体系居里温度在室温以上，并且，研究发现掺杂体系在相同掺杂方式和相同掺杂量的条件下，掺杂体系电子自旋数目不同，磁性显著不同。这对稀磁半导体的磁性增强非常有利。掺杂体系的磁性来源主要由Zn空位产生的空穴为媒介，使得Zn空位附近氧原子中未配对的2p电子轨道自旋极化与Zn3d轨道电子自旋极化双交换作用引起的。第三，用第一性原理研究了Ti/Y/Ag-N/Ni/Fe/Zr/Cd/Cu/V/Mo/Eu分别掺杂在ZnO中的光电磁性能和机理影响，解决了实验上光电磁性能的认识频有争议的问题。第四，用第一性原理研究了W/V/Nb/Ce-N/Pr分别掺杂在TiO2中磁光性能和机理影响，也解决了实验上磁光性能的认识频有争议的问题。