The Research On Preparation Of ZnO Nano-material And Photoelectric Devices

Zinc Oxide (ZnO) is a wide band gap semiconductor material, which has a band gap of 3.37 eV at room temperature, its most important characteristic is the high exciton bounding energy of 60 meV. Based on these characteristics, ZnO has potential applications in short wavelength photoelectric devices. Since nanodevices such as ZnO nanowire based nanolasers, solar cells and nanogenerators were obtained, the applications of ZnO nanostructures in the photoelectric field have attracted wide spread interests in the international, which has become a hot spot in the nano-optoelectronic field of the international frontier topics. The dissertation develops the following creative research on the problems of the growth controlled ZnO nanostructures, design and preparation of nanodevices:Exploring chemical vapor deposition method, through controlling the oxygen flux, the conversion from one dimensional (1D) to two dimensional (2D) growth was realized, thus ZnO nanobolt arrays were obtained; exploring hydrothermal method, through adjusting the size of the seed particle and solution concentration, ZnO nanowires with different size were obtained.Exploring hydrothermal method aligned ZnO nanowires array on the ZnO seed film were obtained, the stimulated emission were observed with threshold of 96 KW/cm~2 excited by femtosecond laser in the optically pumped ZnO nanowires; in order to lower the threshold of the stimulated emission, Pt layer as a high reflectivity mirror was fabricated on Si substrate, optical loss has been effectively decreased, thus the threshold of the stimulated emission was further lowered to 17.3 KW/cm~2 for the optically pumped ZnO nanowires.Using p-GaN single crystalline film as template, the quasi continuous ZnO micro-rods was obtained by hydrothermal method with multiple growth, these ZnO micro-rods present periodically arranged structure with parallel sides, and this kind of structure provides excellent resonance cavity. The stimulated emission was observed in optically pumped ZnO micro-rods; using p-GaN as carrier injection layer the heterojunction was formed with ZnO micro-rods, single mode lasing emission located at 407 nm with a full width at half maximum (FWHM) of 0.7 nm was obtained through electroluminescence (EL) measurement. Through comprehensive analysis of the photoluminescence (PL) for the ZnO/GaN heterojunction, optically pumped stimulated emission and EL, the emission was originated from ZnO.Closely packed ZnO nanowire array was fabricated on Si substrate by magnetron sputtering method, the visible and UV dual bands alternative photo-detection was realized through adjusting forward and reverse bias.