Mo、Cr掺杂对ZnO光电特性影响的第一性原理研究

The Effect of Mo and Cr Doping on Photoelectric Properties of ZnO:First Principle Study

采用基于密度泛函理论第一性原理的方法,计算了本征ZnO、Mo掺杂(Mo_(Zn))和Cr掺杂(Cr_(Zn))体系的光电特性,从理论上讨论了掺杂对体系光电特性的影响.Mo_(Zn)、Cr_(Zn)表现为n型半导体,但Mo掺杂使体系带隙变宽,特征光谱发生蓝移,对可见光的吸收能力降低;而Cr掺杂使体系带隙变窄,特征光谱发生红移,拓展了可见光的响应范围.此外,掺杂Mo、Cr后均使ZnO带边朝低能端移动,使电子跃迁容易实现,有效降低了光生电子-空穴对的复合几率.可见Cr掺杂对改良ZnO有积极作用.

The photoelectric properties of intrinsic ZnO,Mo-doped(Mo_(Zn))and Cr-doped(Cr_(Zn))systems have been calculated using a method based on the first principles of density generalization theory,and the effect of doping on the photoelectric properties of the systems has been discussed theoretically.Mo_(Zn) and Cr_(Zn) behave as n-type semiconductors,but Mo doping makes the system bandgap broader and the characteristic spectrum blue-shifted,reducing the absorption ability of visible light;while Cr doping makes the system bandgap narrower and the characteristic spectrum red-shifted,which expands the response range of visible light.In addition,Mo and Cr doping makes the ZnO band edges move towards the low-energy end,which makes the electron jump easy to realize and effectively reduces the composite probability of photogenerated electron-hole pairs.It can be seen that Cr doping has a positive effect on the improvement of ZnO.