二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过...二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过不同浓度的O取代S替换掺杂,发现随着O浓度的增加,带隙值出现先增大后减小的现象;由于O元素的引入,使二维Ag2S结构对称性降低,引起能带及光吸收、光反射的分布离散化.y方向4.56~5.36 e V处光吸收及光反射峰随掺杂浓度增加逐渐减小,且出现明显的蓝移.展开更多
The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattic...The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.展开更多
文摘二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过不同浓度的O取代S替换掺杂,发现随着O浓度的增加,带隙值出现先增大后减小的现象;由于O元素的引入,使二维Ag2S结构对称性降低,引起能带及光吸收、光反射的分布离散化.y方向4.56~5.36 e V处光吸收及光反射峰随掺杂浓度增加逐渐减小,且出现明显的蓝移.
基金supported by the National Natural Science Foundation of China(21173210,21225315,21321002)the National Basic Research Program of China(973 Program,2013CB834603)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09030000)~~
基金Natural Science Foundation of Shanxi Province(No.2009011014)
文摘The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.
