| Summary: | 碩士 === 國立虎尾科技大學 === 光電工程系光電與材料科技碩士班 === 107 === In this study, using radio frequency magnetron co-sputtering system, zinc oxide thin films and aluminum nitride-zinc oxide co-sputtering thin films were prepared by using zinc oxide and AlN targets respectively. Three structures, namely, undoped zinc oxide thin films and barrier layer AlN-zinc oxide thin films, were annealed at 700 degrees in different environments (nitrogen and oxygen). The confinement ability of the thin films was enhanced by adding double heterostructures of barrier layer AlN-ZnO thin films, and the confinement layer of aluminum nitride. Increasing the electron confinement ability can change the luminescent efficiency. Hall measurements and photoinduced fluorescence spectroscopy are used to understand the stacking characteristics of thin films. Oxygen can compensate for the effect of donor ions. The electrical properties show that the nitrogen ambient heat treatment has higher carrier concentration than oxygen. The double heterostructure substitutes for the position of zinc atoms due to the diffusion of aluminum atoms, in addition to inhibiting zinc oxide. The intrinsic defect increases the carrier concentration of the structure and improves the crystallinity of zinc oxide. When the confined layer of aluminum nitride is added, the excess aluminum atoms will diffuse into the active region. The excess aluminum atoms will bond with oxygen to form an insulating effect, which increases the resistivity of the structure and reduces the carrier concentration, resulting in poor crystallinity of zinc oxide. In this study, n-ZnO/p-Si, DH/p-Si and DH/AlN/p-Si heterojunction dipoles are fabricated on p-type silicon substrates. From the current-voltage characteristics, it can be found that when the conduction voltage of AlN-ZnO double heterojunction is 2.62V, the current ratio is 5.15, then the limiting layer of AlN is fabricated. The conduction voltage rises to 2.74V and the current ratio is 40.89. Both of them have good rectification characteristics. The effects of nitrogen heat treatment at different temperatures (700, 500 and 400 degrees) on undoped ZnO thin films, double heterostructures and double heterostructures with aluminum nitride confinement layer were further investigated. From the current-voltage characteristics, it was found that the series resistance and start-up voltage of the components decreased with the increase of nitrogen heat annealing temperature. The double heterostructures of AlN-ZnO thin films were electrically conductive at 400 degrees nitrogen. Voltage is 2.00V and current ratio is 9.13. When the temperature rises to 500 degrees, the on-line voltage drops to 1.88V and the current ratio is 10.45. When the temperature reaches 700 degrees, the lowest on-line voltage is 1.80V and the current ratio is 11.68.
|
|---|
