Synthesis Of One-dimensional Zno Nanomaterial And Research Of Its Electroluminescent Device

Znic oxide (ZnO), an important semiconducting oxide with a wide-direct bandgap (3.37eV) and a large exciton-binding energy (60meV) at room temperature, isconsidered as a promising material for various photonic and electrical applicationsdue to its special physical and chemical properties. ZnO can emit ultraviolent orvisible lights in a wide range due to a number of intrinsic and extrinsic defects in it. Inthis dissertation, we firsly prepared ZnO nanorods by a simple but refined method,and then fabricated a ZnO EL device with the structure of ITO/ZnO nanorods/PVK/Al.Their EL mechanisms are also studied.First, ZnO nanorod arrays have been prepared by templete method and chemicalbath deposition method, respectively. In view of the applications in eleltroluminescentdevice, we focused on the preparation conditions of ZnO nanorods by chemicaldeposition method. The as-grown ZnO nanorods have wurtzite structure, exhibiting apreferable orientation of [002] direction. Moreover, the effect of growth conditions onthe microstructure and optical properties of ZnO nanorods has been studied. Thismethod has drawn extensive interests because of the low growth temperature(＜100℃), low cost and good potential for scale-up with general substrates. Also thistechnique brings the possibility of creating patterned nanostructures for applicationsas optoelectronic devices.Secondly, we fabricated ITO/ZnO nanorods/PVK/Al electroluminescencedevice. In order to realize the EL emitting of ZnO and to analyze the luminescencemechanism of the device, we also fabricated ITO/ZnO/Al and ITO/PVK/Alelectroluminescent devices for comparison, and measured the I-V curve and the ELspectra of the devices. There is a large hole barrier between ITO and ZnO, so that itlimits the luminescence of the device to some extent. In the thesis the invertedelectroluminescence device with a structure of ITO/ZnO nanorods/PVK/Al iscreatively fabricated, and the luminescence intensity of the device has beeneffectively enhanced. Both ultraviolet emission peak at379nm and the emission ofdefects at520nm,572nm and760nm were detected. So we proposed the possible wayto realize the white-coloured EL device without doping and without p-n junctionstructure.Sharp peaks were observed both in the EL spectra of the set structure and inverted structure. According to the correlated theory, the sharp peaks, as the electricallypumped random lasing, were generated by the light-emitting devices. Every sharppeak corresponded to a spontaneous emission process. During multiple scatteringprocesses，the spontaneously emitted light will attain optical gain which is overoptical losses. As the optical gain surpasses the losses, random lasing consequentlyoccurs. It is indicated that the vertically aligned growth and uniform heights of ZnOnanorods are critical for the generation of random lasing from the EL devices basedon the ZnO nanorod arrays. The discovery of random lasing made ZnO nanorods havemore potential applications in optoelectronic devices.