Shiying Liu

Transparent ZnO:Al2O3 films with high breakdown voltage and resistivity

Transparent ZnO films with high breakdown voltage and resistivity were deposited by the radio frequency-assisted evaporation method. In this paper, we have investigated on the structural, optical, and electrical properties of ZnO:Al2O3. The preferred orientation of the columnar structured in situ-grown film was along (002). The resistivity of the films was five orders of magnitude larger than the currents highest resistivity. The breakdown voltage of the film (8571 V/mm) was five times higher than the highest reported breakdown voltage for a ZnO semiconductor. Furthermore, the ZnO:Al2O3 film was transparent in the visible and infrared regions even though the film had an Al content of about 7% and a thickness of 100 nm. The high-frequency dielectric constant of the ZnO:Al2O3 film was higher than that of Al2O3. The possible reasons for the transparent ZnO:Al2O3 film behavior were second-phase Al2O3, lower carrier concentration, and strong bound electrons. Less defects and strong bonding contribute 4 orders of magnitude improvement to the high resistivity of ZnO films. The obtained results suggest that ZnO:Al2O3 can be used as an insulator layer between the p-n junction in order to improve the efficiency of the solar cell device.Transparent ZnO films with high breakdown voltage and resistivity were deposited by the radio frequency-assisted evaporation method. In this paper, we have investigated on the structural, optical, and electrical properties of ZnO:Al2O3. The preferred orientation of the columnar structured in situ-grown film was along (002). The resistivity of the films was five orders of magnitude larger than the currents highest resistivity. The breakdown voltage of the film (8571 V/mm) was five times higher than the highest reported breakdown voltage for a ZnO semiconductor. Furthermore, the ZnO:Al2O3 film was transparent in the visible and infrared regions even though the film had an Al content of about 7% and a thickness of 100 nm. The high-frequency dielectric constant of the ZnO:Al2O3 film was higher than that of Al2O3. The possible reasons for the transparent ZnO:Al2O3 film behavior were second-phase Al2O3, lower carrier concentration, and strong bound electrons. Less defects and strong bonding contribute 4 orders...

Effect of high magnetic field on magnetic properties of oxidized ZnO:Co film prepared with different growth models

Growth models and high magnetic field (HMF) are employed to affect diluted magnetic performance of Co-doped ZnO (ZnO:Co) films which oxidize Co-Zn evaporated films at 300 °C for 120 min in open air. Nanograined boundaries and dense structure obtained in the co-deposition films are helpful to present a better diluted magnetic performance. Two phases of Zn and ZnO coexist in the films at a low oxidation temperature. Both the bilayer Co/Zn film and the application of HMF during the oxidation process offer an easy way to increase oxygen vacancies, which are inconducive to improve the ferromagnetism. The co-deposition 0 T film has the best diluted magnetic performance compared with the bilayer 0 T film. To be specific, saturation magnetization MS of the co-deposition 0 T film (100.1 emu/cm3) increases by 190%, squareness S increases from 0.31 to 0.75 and coercivity HC increases from 34.6 Oe to 183.5 Oe. With the application of HMF, the MS of the co-deposition films decreases by 44% to approximately 55.8 emu/cm3 and the HC increases to 118.4 Oe.Growth models and high magnetic field (HMF) are employed to affect diluted magnetic performance of Co-doped ZnO (ZnO:Co) films which oxidize Co-Zn evaporated films at 300 °C for 120 min in open air. Nanograined boundaries and dense structure obtained in the co-deposition films are helpful to present a better diluted magnetic performance. Two phases of Zn and ZnO coexist in the films at a low oxidation temperature. Both the bilayer Co/Zn film and the application of HMF during the oxidation process offer an easy way to increase oxygen vacancies, which are inconducive to improve the ferromagnetism. The co-deposition 0 T film has the best diluted magnetic performance compared with the bilayer 0 T film. To be specific, saturation magnetization MS of the co-deposition 0 T film (100.1 emu/cm3) increases by 190%, squareness S increases from 0.31 to 0.75 and coercivity HC increases from 34.6 Oe to 183.5 Oe. With the application of HMF, the MS of the co-deposition films decreases by 44% to approximately 55.8 emu/cm...