Fabrication And Properties Investigation On Phosphorus Doped ZnO Nanostructures And Nanowires Homojunction LED

ZnO is a typical kind of II-VI clan direct wide band gap semiconductor materials, itsband gap width is3.37eV and exciton binding energy reaches up to60meV, which is muchgreater than26meV at room temperature, so it is regarded as well materials of making shortwavelength optoelectronic devices and preparing room temperature ultraviolet laser devices(LEDs); Also with the abundant features, ZnO nanomaterials have broad applicationprospects in different fields of catalysis, sensing, and biochemical.In order to realize the application of ZnO photovoltaic material, high-quality p-type ZnOnanomaterial is needed. However, how to obtain high-quality p-type ZnO nanomaterialsbecomes the hotpots and difficulties in both domestic and foreign research. In this thesis,according to the difficulties and problems of preparing for the p-type ZnO nanostructures atpresent, we use self-assembly chemical vapor deposition (CVD) equipment, differentmorphological appearance of the phosphorous doped ZnO nanostructures are prepared bychanging the position of substrate; ZnO homojunction light emitting diodes are prepared bythe method of secondary growth. Meanwhile, their structures and features have been studied.The main achivements are listed as follows:(1) The different morphologies and structures of phosphorus doped ZnO nanomaterialsare prepared by changing the substrate position in Si (100) substrate and by chemical vapordeposition method without using catalyst Through field emission scanning electronmicroscopy (FE-SEM) and transmission electron microscopy (TEM) to get observationsabout the reaction source in the downstream and the sample at the top respective arephosphorus doped ZnO nanowires and phosphorus doped ZnO nanonails, which both have agood orientation. In addition, we also have analysis on the growth mechanism of differentnanostructures. From the spectrums of the energy dispersive spectrum (EDS), we observephosphorus mole percentages are both about2%in the two pieces of samples. Thephosphorus related acceptor emissions (A0X) were observed from thetemperature-dependence photoluminescence spectra of phosphorus-doped ZnO nanostructures,so we confirmed that the phosphorus as acceptor doping access to ZnO.(2) The phosphorus-doped ZnO nanowires/n-ZnO nanowires/n-Si homojunctions were synthesized by simple chemical vapor deposition method on the low resistance Si (100)substrate. The high quality n-type ZnO nanowires are prepared without any doping source,then the phosphorus doped p-type ZnO nanowires are prepared by using the method ofsecondary growth. The measurements show that the device has good rectifying characteristics,the positive open voltage is4.6V, and the reverse breakdown voltage is9.7V. Theelectroluminescence spectrum was obtained on the ZnO nanowires homojunctions at roomtemperature with a weak ultraviolet emission peak at3.18eV and a broad visible bandcentered at1.90eV. Under the condition of positive40mA injection current, the device getsthe electroluminescent at room temperature. In electroluminescent spectra, it presents twoluminescent peaks, one is the UV luminescence peak at3.19eV, the other is the visiblephotoluminescence peak at1.90eV. The results confirmed that the phosphorus doped ZnOnanowires is the p-type conductive properties.