p型K:ZnO导电机理的第一性原理研究

基于密度泛函理论，利用局域密度近似的第一性原理平面波赝势方法，对掺K以及含有氢填隙(H_i)、氧空位(V_O)、锌填隙(Zn_i)和锌空位(V_Zn)的K:ZnO电子结构分别进行了研究.结果表明，1) 单独掺K可引入浅受主，但系统总能增高；2) K与H共掺可降低系统总能，提升稳定性；3) V_O在K+H:ZnO中的形成比Zn_i困难得多，二者都是关键词：氧化锌p型第一性原理电子结构

First principles investigation on conductivity mechanism of p-type K:ZnO

The electronic structures of potassium doped ZnO have been calculated by first principles plane wave-function psuedopotential approach based on density-functional theory and local density approximation. Properties of some defects were studied in order to explicate the conductivity mechanism of p-K:ZnO, including hydrogen interstitial (H_i), oxygen vacancy (V_O), zinc interstitial (Zn_i) and zinc vacancy (V_Zn). The calculated results revealed that: (1) K-doping introduced a shallow acceptor,besides increasing the system total energy simultaneously. (2) K-H:ZnO decreased the system energy and increased the system stability. (3) Although the formation of V_O was more difficult than that of Zn_i, both of them were electronegative centers and played a role in compensating for the acceptors. (4) V_Zn produced_a shallow acceptor approximately 0.5 eV above the maximum valence band, which was beneficial for p-type conductivity. Finally, it was proposed that the realization of p-type conductivity in K:ZnO may be due to the formation of a K_Zn-O-H_i-O-V_Zn complex.