The Ga203/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga203 layers are in a range of 19 nm-2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Form...The Ga203/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga203 layers are in a range of 19 nm-2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Formation of spinel ZnGa204 film is achieved via the annealing of the Ga203/ZnO multilayer film. The influences of original Ga203 sublayer thickness on the optical and structural properties of Ga203/ZnO multilayer films and annealed films are studied. With the decrease of the thickness of Ga203 sublayer, the optical band-gap of Ga203/ZnO multilayer film decreases, the intensity of UV emission diminishes and the intensity of violet emission increases. The annealed film displays the enlarged optical band gap and the quenched violet emission. UV fluorescence bands are observed from Ga203 and ZnGa204.展开更多
Defect formation energies, electronic structures and optical properties of Sn-doped β-GazO3, F-doped β-Ga2O3, and Sn/F co-doped β-Ga2O3 were calculated using the first-principles. The calculated results of the pure...Defect formation energies, electronic structures and optical properties of Sn-doped β-GazO3, F-doped β-Ga2O3, and Sn/F co-doped β-Ga2O3 were calculated using the first-principles. The calculated results of the pure and Sn-doped β-Ga2O3 using the local-density approximation （LDA） method show that the lattice parameters and electronic structures are in agreement with previous data. The defect formation energies demonstrate that the doped systems are relatively easy to form under O-rich conditions. Sn-doping, F-doping and Sn/F co-doping make β-Ga2O3 become an n-type semiconductor. Sn/F co-doping β-Ga2O3 has the smallest effective electron mass and the biggest relative electron number, which is expected to possess good conductivity. Sn/F co-doping β-Ga2O3 displays an intense absorption in visible light.展开更多
The p-type N-doped PbTiO3 with different doping concentrations have been studied by first-principles calculations. The charge density differences, band structures, density of states and optical properties have been in...The p-type N-doped PbTiO3 with different doping concentrations have been studied by first-principles calculations. The charge density differences, band structures, density of states and optical properties have been investigated. After an oxygen atom is substituted by a nitrogen atom in the crystals, the valance bands move to high energy levels and the Fermi energy level gets into the top of the valance bands. Results show that the values of the band gaps are decreased and the stability is weakened when the N concentration increases. The 2.5 at% N-doped PbTiO3 shows the best p-type conductivity and the visible-light absorption can be enhanced most at this doping concentration, which is necessary in semiconductors or photocatalysts.展开更多
基金The National Natural Science Foundation of China(No.10974077)Natural Science Foundation of Shandong Province,China(No.2009ZRB01702)Shandong Province Higher Educational Science and Technology Program(No.J10LA08)
基金Project supported by the National Natural Science Foundation of China(Grant No.10974077)the Innovation Project of Shandong Graduate Education,China(Grant No.SDYY13093)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2010AL026)
文摘The Ga203/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga203 layers are in a range of 19 nm-2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Formation of spinel ZnGa204 film is achieved via the annealing of the Ga203/ZnO multilayer film. The influences of original Ga203 sublayer thickness on the optical and structural properties of Ga203/ZnO multilayer films and annealed films are studied. With the decrease of the thickness of Ga203 sublayer, the optical band-gap of Ga203/ZnO multilayer film decreases, the intensity of UV emission diminishes and the intensity of violet emission increases. The annealed film displays the enlarged optical band gap and the quenched violet emission. UV fluorescence bands are observed from Ga203 and ZnGa204.
基金supported by the National Natural Science Foundation of China(No.10974077)the Innovation Project of Shandong Graduate Education,China(No.SDYY13093)
文摘Defect formation energies, electronic structures and optical properties of Sn-doped β-GazO3, F-doped β-Ga2O3, and Sn/F co-doped β-Ga2O3 were calculated using the first-principles. The calculated results of the pure and Sn-doped β-Ga2O3 using the local-density approximation （LDA） method show that the lattice parameters and electronic structures are in agreement with previous data. The defect formation energies demonstrate that the doped systems are relatively easy to form under O-rich conditions. Sn-doping, F-doping and Sn/F co-doping make β-Ga2O3 become an n-type semiconductor. Sn/F co-doping β-Ga2O3 has the smallest effective electron mass and the biggest relative electron number, which is expected to possess good conductivity. Sn/F co-doping β-Ga2O3 displays an intense absorption in visible light.
基金Project supported by the National Natural Science Foundation of China(No.10974077)the Innovation Project of Shandong Graduate Education,China(No.SDYY13093)
文摘The p-type N-doped PbTiO3 with different doping concentrations have been studied by first-principles calculations. The charge density differences, band structures, density of states and optical properties have been investigated. After an oxygen atom is substituted by a nitrogen atom in the crystals, the valance bands move to high energy levels and the Fermi energy level gets into the top of the valance bands. Results show that the values of the band gaps are decreased and the stability is weakened when the N concentration increases. The 2.5 at% N-doped PbTiO3 shows the best p-type conductivity and the visible-light absorption can be enhanced most at this doping concentration, which is necessary in semiconductors or photocatalysts.
