One-dimensional Growth Mechanism Of The Optical And Electrical Properties Of Zno

The one-dimensional ZnO structures have become the hotspot in recent years because of the superior performance in the properties of field emission,ultraviolet sensitive,piezoelectric etc,and these properties make it have the potential applications in the areas of flat panel display,ultraviolet sensor and micro nano-generator.However, one of the most important obstacles of application is difficult to prepare the well allied and oriented one-dimensional ZnO array.Therefore,in order to solve this problem,it is essential to investigate the growth mechanism and process of one-dimensional ZnO structures.In this thesis we have prepared the samples by chemical vapor deposition in different substrates and the samples were characterized and analyzed by X-ray diffractometry,scanning electron microscopy,energy-dispersive X-ray spectroscopy and Photoluminescence spectrometer.Spontaneous nucleation of one-dimensional ZnO structure based on the vapor-solid(V-S) growth mechanism was investigated.It was found that the crystalline nucleus could not form in low temperature,and the exorbitant temperature lead to the chaos of growth direction.The one-dimensional ZnO structures were also prepared on the sapphire(0001),(11(?)0) and Si(100) substrates.The different growth direction on different substrate was explained in term of the crystal lattice mismatch theory.In addition,the photo-electronic properties of one-dimensional ZnO array were studied in this thesis.The current-voltage characteristics under ultraviolet irradiation (λ=256nm) indicates that the sensitivity properties were depend on the growth direction. Horizontal growth direction one-dimensional ZnO array was 4.54 and the response time was 1.550s.By comparison,the vertical one-dimensional ZnO array was 20.18 and 0.014s.The reason of the tremendous performance was caused by the irradiation areas.Finally,the Ga-droped Quasi-one-dimensional ZnO structures are prepared by using the Ga₂O₃ and ZnO mixture source(Mass ratio=1:3).Ga atoms cause the lattice constant decrease.The Photoluminescence spectrum indicates a new peak in 410nm which have not been observed in non-dropped one-dimensional ZnO structures.