氧空位浓度对氧化锌电阻阀片电学性质的影响

Effect of oxygen vacancy concentration on the electrical properties of zinc oxide resistors

为研究氧空位浓度对氧化锌电阻阀片电学性质的影响,在微观层面上模拟了5种不同氧空位浓度的ZnO晶体模型.基于第一性原理计算了各模型体系的晶体结构、氧空位形成能、能带结构、态密度、载流子有效质量及电导率等.结果表明,随着氧空位浓度的增加,晶格常数和体积均随之减小,导致ZnO晶粒尺寸减小,单位厚度的晶界数量增加和压敏电压增大,氧空位形成能逐渐增大,高浓度氧空位形成越困难.在含有氧空位的体系中均产生了深能级电子陷阱,并且不同氧空位浓度产生的深能级电子陷阱俘获载流子的陷阱效应不同.在温度一定时,随着氧空位浓度的增加,ZnO的电导率逐渐减小,导电性能变弱,所得结果与实验相一致.

In order to study the effect of oxygen vacancy concentration on the electrical properties of zinc oxide resistors, five kinds of zinc oxide crystal models with different oxygen vacancy concentration were simulated at the micro level. The crystal structure, oxygen vacancy formation energy, energy band structure, density of states, effective mass of carriers, and electrical conductivity of each model system were calculated based on the first principle. The results show that with the increase of oxygen vacancy concentration, the lattice constant and volume decrease, resulting in the decrease of grain size of ZnO, the increase of the number of grain boundaries per unit thickness and the increase of pressure-sensitive voltage per unit thickness. Oxygen vacancy formation can gradually increase with the increase of oxygen vacancy concentration, and the formation of high concentration oxygen vacancies becomes more difficult. Deep-level electron traps are generated in systems containing oxygen vacancies, and the trapping effects of deep-level electron trap carriers generated by different oxygen vacancy concentrations are different. At certain temperature, with the increase of oxygen vacancy concentration, the conductivity of ZnO decreases gradually. The results are consistent with the experiment finding.