Preparation And Properties Of Ga-and Li-doped ZnO Nanoparticle/Nanorod Arrays

ZnO is a direct bandgap semiconductor with a bandgap energy of 3.37eV, and has a potential application in short-wavelength optoelectronic devices. However, such application requires a high-quality p-type ZnO and its p-n homojunctions. A possible approach is to build a p-type nanoparticle/n-type nanorod or n-type nanoparticle/p-type nanorod junction which could enhance the transmission of carriers. In this work, we mainly focus on the preparation of the ZnO nanoparticle/nanorod structure and the corresponding ZnO p-n homojunction, which is of great fundamental and practical significance.In the case of Ga-N codoping, an Ga3+-doped ZnO film was first prepared by sol-gel method. And then N was doped through PECVD technique in NH3 atmosphere to obtain Ga-N codoping in the film. Furthermore, ZnO nanorods grown on the Ga-N codoped film were achieved based on seed-grown method from a solution containing Zn2+ to form the p-n homojunction. The ZnO films and nanorod arrays were characterized by XRD, FE-SEM, UV-vis, photoluminescence, Hall effect and electroluminescence. With an increasing of Ga3+ content, crystal quality, grain size, energy gap and UV-luminescent intensity of ZnO films decrease gradually. It was found that Ga-N codoped ZnO film with 0.6at%Ga displays p-type behavior. And according to the EL spectra, a defect-related blue electroluminescence at 456nm of ZnO homojunction was observed when the injection voltage is 10V. Such a blue light emission is expected to have a potential application in short-wavelength optoelectronic devices.In the case of Li-doping, Li+-doped ZnO nanoparticle films were prepared by sol-gel method, and the corresponding ZnO nanorod arrays were grown on the film form a low-temperature solution containing Zn2+. The influence of Li+-doping on the property of ZnO nanorod arrays was studied by XRD, FE-SEM, UV-vis, and PL. Results indicate that Li+-doping in the film can not only increase the crystal quality, grain size and PL intensity of ZnO but also improve the crystallization and c-axis orientation of ZnO nanorods. In particular, the UV-luminescent intensity of ZnO nanorod arrays were greatly enhanced under such conditions, which is of great significance in realization of pure UV light-emitting nanorod arrays.