Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the...Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the twin GBs can facilitate the formation and aggregation of Ag substitution at Zn sites(AgZn)due to the strain release.Meanwhile,some twin GBs can also lower the ionization energy of AgZn.The density of state shows that the O–O bonds in GBs play a key role in the formation of a shallow acceptor energy level.When AgZnbonds with one O atom in the O–O bond,the antibonding state of the O–O bond becomes partially occupied.As a result,a weak spin splitting occurs in the antibonding state,which causes a shallow empty energy level above the valence band maximum.Further,the model can be applied to explain the origin of p-type conductivity in Ag-doped Zn O.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11364009)Natural Science Foundation of Guangxi Province,China(Grant No.2014GXNSFFA118004)
文摘Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the twin GBs can facilitate the formation and aggregation of Ag substitution at Zn sites(AgZn)due to the strain release.Meanwhile,some twin GBs can also lower the ionization energy of AgZn.The density of state shows that the O–O bonds in GBs play a key role in the formation of a shallow acceptor energy level.When AgZnbonds with one O atom in the O–O bond,the antibonding state of the O–O bond becomes partially occupied.As a result,a weak spin splitting occurs in the antibonding state,which causes a shallow empty energy level above the valence band maximum.Further,the model can be applied to explain the origin of p-type conductivity in Ag-doped Zn O.
