补偿型共掺杂ZnS电子特性的第一性原理计算

First Principle Study of Electronic Properties of Compensational Codoped ZnS

基于密度泛函理论的第一性原理平面波赝势方法,对ZnS(Cu,Cl、Br、I)共掺杂体系的晶格结构和电子性质进行了研究。结果表明,相对于单掺杂ZnS体系,补偿型的共掺ZnS体系形成能更低,更有利于提高可见光的催化效率,且由于p-d电子排斥效应使价带向高能方向展宽,而Cu的3p态与非金属原子的杂质态使导带底下移,从而使共掺杂ZnS体系的能带带隙变窄,尤其是CuZnBrS-ZnS带隙值减少了30%,从而延伸吸收边界到可见光区域。且CuZnBrS-ZnS中m*e/m*h相对较大,降低了电子-空穴对重组率,提高了量子效率。最后对补偿型共掺ZnS电子结构进行了讨论。

The lattice structure and electronic properties of pure,doped（Cu;Cl,Br,I）and codoped ZnS were calculated by first-principles ultra-soft pseudopotential approach of the plane wave.The calculated results show that the compensation codoping have smaller formation energy compared with doped ZnS and are beneficial for improving the catalytic efficiency of visible light.Meanwhile,p-d rejection effect between Cu 3 dstate and nonmetal impurities 3 p state on the top of valence band,which makes it move to higher energy side,the interaction between doped impurities move down conduction band to lower energy.Both of the effect result in the band gap narrowing,especially for CuZnBrS-ZnS,charge-compensated donor-acceptor pair,leads to an about 30%reduction of the energy gap,thus extending the absorption edge to visible light region.Moreover,the larger value of m＊e/m＊hin CuZnBrSZnS result in a lower recombination rate of the electron-hole pairs and efficient for light to current conversion in codoped ZnS.Therefore,the discussion of compensation codoping ZnS,pointed out the application prospect of design and synthesis codpoped ZnS in the field of photocatalysis.