The Surface And Interface Barrier Of ZnO One-dimensional Nanostructure Through Sulfuration Control And Its UV Detection Feature

The zinc oxide of wurtzite structure is a wide-bandgap of direct bandgap semiconductor material, and its wide band gap 3.37 eV and larger exction binding energy 60 meV. Due to the nano-sized ZnO with a large specific surface area, small size effect, quantum effect and dielectric confinement effects, etc. It exhibits many specific properties like optical, electrical and photocatalytic characteristics and can be widely used in solar cells, light emitting diodes, field-effect transistors, gas devices and ultraviolet detectors,etc.Studies have shown that, due to the ZnO nanowire surface has a complex surface states, oxygen can be adsorbed onto the surface of ZnO, and photocurrent mechanism mainly relies on adsorption and desorption of oxygen which is a relatively slow process. When in the oxygen-free environment such as vacuum, the response time of the device is relatively long and the performance of the photodetector decreases. In order to increase the sensitivity of the detector as well as to reduce the response time, given by forming a shell to prepared II core-shell structure to regulate the surface barrier. Based on such II structure can effectively separate the electron and hole, it is possible to improve the stability and response rate of the photodetector,thus we can prepare high-performance devices and to develop a novel(ultra-violet) UV detector without oxygen adsorption.Based on our group in this area, this paper mainly includes the following aspects:The first chapter is mainly to introduce the progress of one-dimensional nanomaterials optoelectronic devices, the growing technical of ZnO nanowire arrays and the background of core-shell heterostructure. In addition to, we illustrate some specific performances of type II core-shell structure nanomaterials.The second chapter, we use hydrothermal to synthesis ZnO nanowires array structure, and by control the hydrothermal reaction time, temperature and the concentration of the hydrothermal reaction precursor,we successfully prepared a good crystallinity ZnO nanowire arrays structure. Then through high temperature sulfuration for preparing ZnS shell layer, the ZnO/ZnS core-shell nanowire arrays were synthesised and to characterize the structure and morphology.The third chapter is to spin-coat PMMA plastic on the ZnO nanowire arrays and ZnO/ZnS core-shell nanowire arrays. Then though reactive ion beams etching technology to expose the top of nanowires and byevaporation to prepare electrode on the top of nanowires, thus we can make the optical detection device.Then we studied the current-voltage(I-V) curve characteristics and light current change with time of the Zn O nanowire arrays and ZnO/ZnS core-shell nanowire arrays.By comparing photocurrent change characteristics before and after UV irradiation to research photocurrent mechanism of photodetector. Thus we can prepare highly stable performance photodetector.The fourth chapter is to sulfuration the CdO/ZnO ultrafine core-shell nanowires s at high temperature.At the same time we analyze the morphology and basic composition of the sample.Then we studied the current-voltage(I-V) curve characteristics and light current change with time of the devices.By comparing photocurrent change characteristics before and after UV irradiation of different sulfuration time to study the photocurrent mechanism in the air atmosphere and vacuum atmosphere, which to develop a novel UV detector without the participation of oxygen adsorption.