Preparation And Performance Study Of ZnO And ZnMgO Nano Materials By Hydrothermal Method

As a new II-VI wide semiconductor material, ZnO owns a wide direct band gap of 3.37eV and a large exciton binding energy of 60meV at room temperature. In addition, because of these advantages such as abandant in raw materials, low cost and environmentally friendly, ZnO has great application prospect in ultraviolet photo-electirc field. Due to their unique morphologies and excellent performance, low dimensional ZnO nano materials have attracted global attention. Although researches have been conducted and many achievements have obtained, yet there still exited lots of confusions on controllable synthesis, effective doping and device fabrication.In this paper, different morphologies of ZnO nanostructured materials, including one-dimensional ZnO nanoshuttle and one-dimensional ZnO nanorod arrays, have been synthesized by hydrothermal method. Besides, we prepared Mg doped ZnO ND arrays in this way. At the same time, structures and properties of these materials were also characterized and analyzed. The main conclusions are summarized as following:(1) One-dimensional ZnO nanoshuttles synthesized using hydrothermal method, were consistent in morphology and uniform in size. The process was reliable and reproducible. Through analysis on reaction pricinple and growth mechanism, shuttled ZnO nano material was obtained because the opposite two tips of nanorod decomposed due to pH increased as reaction continued.(2) ZnO NRAs were synthesized by floating the substrate in the solution. Through process parameters optimization and analysis, the final acquired optimized parameters include:1) the substrate placed by suspension way; 2) the concentration of the solution close to 0.025mo 1/L; 3) the reaction temperature ranging between 90℃and 95℃; 4) the reaction time ranging from 12h to 24h; 5) the seed layer prepared by PLD method. ZnO ND arrays synthesized according to the optimized parameters were good in crystallization performance, regular in morphology, uniform in size and had c axis preferred orientation.(3) Zn1-xMgxO NRAs were synthesized under particular condition with different Mg content, the highest Mg content in Zn1-xMgxO NRAs we obtained was no more than 0.04, regardless of the Zn-to-Mg ratios in solutions, which is almost the same as the thermodynamic solubility limit. The UV luminescence was predominant in PL spectra and could be tuned from 378 to 373 nm at room temperature at x=0-0.04. TheⅠ-Ⅴcharacteristics of Zni1-xMgxO NRAs photodetectors were measured and revealed that the on/off current ratios increased from 3 to 103 as x increased from 0 to 0.04. The significant photodetective behaviors would be attributed to the abundant and different defects at high Mg contents. This study is expected not only to provide an insight into the fundamental understanding of low-temperature sysnthesis of Zn1-xMgxO nanostructures by hydrothermal but also to make a significant technical advance on the device fabrication in this system.