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本文运用密度泛函理论系统地研究了N和X(X=S,Se,Te)共掺杂锐钛矿TiO2时电子特性所受的影响。优化后的结构表明,在锐钛矿TiO2共掺杂时,由于掺杂原子有较大的原子半径而引起了大的晶格膨胀。从计算的替换能结果看,当X(X=S,Se,Te)掺杂到有N原子存在的TiO2时,若替换Ti原子,则不能很好地促进与N的协同作用,若替换O原子,则相反。从总态密度图和分态密度图来看,替换O原子后的N2p轨道和其他杂质带S 3p,Se 4p,Te 5p杂化在一起;同时替换Ti原子后,导带主要由Ti 3d轨道所占据,从而形成了S 3p(Se 4p or Te 5p)-N2p-Ti 3d杂化态。从Bader电荷的结果可知,替换O原子,电子转移是由N到X(X=S,Se,Te),而替换Ti原子后,电子转移是由X(X=S,Se,Te)到N。
In this paper, the effects of N and X (X = S, Se, Te) co-doping with anatase TiO2 on the electronic properties were studied systematically using density functional theory. The optimized structure shows that there is a large lattice expansion due to the larger atomic radius of the doping atoms in anatase TiO2 co-doped. From the results of calculated substitution energies, when X (X = S, Se, Te) is doped into TiO2 with N atoms, the substitution of Ti atoms can not promote the synergy with N well. If O Atoms, on the other hand. From the total state density diagram and the state-of-matter density diagram, the N2p orbitals replaced by O atoms are hybridized with other impurity bands S 3p, Se 4p and Te 5p. At the same time, the Ti band is mainly composed of Ti 3d orbitals Occupies, resulting in the S 3p (Se 4p or Te 5p) -N2p-Ti 3d hybrid state. From the result of Bader charge, we can see that for the replacement of O atoms, the electron transfer is from N to X (X = S, Se, Te) .