Ga-F共掺杂ZnO导电性和透射率的第一性原理计算

用基于密度泛函理论的第一性原理平面波超软赝势方法,对本征ZnO,Ga、F单掺ZnO和Ga-F共掺ZnO的几何结构进行优化后计算了各体系的相关性质.结果表明各掺杂体系有各自的优缺点,在制作透明导电薄膜时可根据具体要求采取不同的掺杂方案.Ga掺杂ZnO比F掺杂ZnO的晶格畸变小.相同环境下Ga原子比F原子更容易进入ZnO晶格,因此掺杂后结构更加稳定.Ga、F掺杂都改善了ZnO的导电性,掺杂ZnO的载流子浓度比本征ZnO增加了3个数量级,相同浓度的F掺杂比Ga掺杂能产生更多的载流子.Ga-F共掺杂ZnO折中了上述Ga、F单掺杂ZnO的优缺点.另外,掺杂后ZnO的吸收边蓝移,以Ga-F共掺杂ZnO在紫外区域的透射率最大,在280~380 nm范围内其透射率在90%以上.

First-Principles Calculation on the Conductivity and Optical Transmittance of ZnO Codoped with Ga-F

The related properties of intrinsic, Ga-, F- doped and Ga-F codoped ZnO are calculated after making geometry optimization using first principles plane-wave ultrasoft pseudopotential method based on the density functional theory. The results show that every doped ZnO has its own advantages and disadvantages, so there is different doping scheme according to specific requirement. The lattice distortion in Ga doped ZnO is smaller than F doped ZnO. And Ga doped ZnO has more stable structure than F doped ZnO, since Ga atoms are more likely to enter the ZnO lattice than F atoms under the same environment. Doping Ga and F improves the conductivity of ZnO. Compared with intrinsic ZnO, the carrier concentration of doped ZnO is increased by three orders of magnitude. And doping Ga can produce more carriers than doping F in the same concentration. Ga-F codoped ZnO reaches a compromise between merits and demerits of these properties above in Ga-doped and F-doped ZnO. In addition, the optical absorptions of doped ZnO generate a blue shift. The optical transmittance of Ga-F codoped ZnO is the biggest in ultraviolet region, and it is higher than 90% in 280~380 nm range.