【作者】 王红军；

【导师】 付德君；

【作者基本信息】 武汉大学 ， 粒子物理与原子核物理， 2012， 博士

【摘要】 ZnO是一种直接宽带隙半导体材料，室温下禁带宽度为3.37eV，激子束缚能为60meV，可以实现高温或是室温下的具有很高效率的激子受激发光过程，因此在波长较短的光电器件中有着潜在的应用价值，是制备半导体激光器（LDs）、紫外光发光二极管（LEDs）等器件的理想材料。由于ZnO的（002）晶面的表面自由能最低，因而具有沿着（002）的方向取向性生长特性，所以一维的ZnO纳米结构比较容易成功制备。ZnO在光电、铁电、热电等很多领域有着潜在的应用价值，尤其在低维材料中，由于量子约束效应，ZnO具有更加优异的光电特性。因此，纳米结构的ZnO在纳米光电子器件和纳米电子器件方面有巨大的应用价值。本论文首先研究ZnO材料的制备方法及对结构与性能的测试分析，然后重点研究一维ZnO纳米结构在电阻开关存储器和气体探测器方面的应用，具体分为以下几个部分：1. ZnO材料的制备和表征。利用气相输运法制备了一维ZnO纳米结构，并重点研究了其光学性质。选择定向性好的ZnO纳米棒为研究对象，其在10K温度下测试的PL谱线几乎没有缺陷发射峰，说明ZnO纳米棒具有很好的晶体质量。随着温度的增加，带隙发射峰出现红移的现象。随着温度的进一步升高，D⁰X发射峰的强度逐渐降低而自由激子发射峰的强度增加并逐步站主导地位。在氧气氛围下退火可以调高ZnO薄膜的晶体质量和光学性质，在700℃的得到晶体质量最好。2.阻性存储研究。首先制备Au/ZnO NWNs/ITO （MIM）结构，其中ITO薄膜同时作为生长ZnO的衬底和MIM结构的一个电极，厚度为100nm的Au电极是用模板通过热蒸发的方式沉积在ZnO纳米材料上的。I-V测试表明，MIM结构呈现双极性电阻开关特性，具有较大的R_on/R_off比，并具有良好的稳定性和可重复性。阻性开关导电机制是由ZnO纳米结构表面氧空穴导电通道的形成和断裂过程实现的。3.气体探测器研究。制备了基于Pd纳米颗粒附着的定向ZnO纳米棒阵列（Pd/ZnO），作为阳极材料进行了场电离实验。结果表明相对于基于光滑的ZnO纳米棒阵列的气体探测器，基于Pd/ZnO的探测器具有更小的击穿电压，并有很好的稳定性和重复性。对惰性气体也具有探测功能和指纹特性。更多还原

【Abstract】 Zinc oxide, as a semiconductor with a direct wide band gap of3.37eV andexciton energy of60meV, favors the excitonic emission even at high temperature.Therefore, the ZnO has the great potential for the production of optoelectronic devices,such as light-emitting diodes and laser diodes. Because of the lower surface freeenergy of the （002） plane, ZnO usually is grown along the c-axis orientation. As aresult, one-dimensional ZnO nanostructures are more successfully to be synthesized,such as nanowires, nanobelts, nanotubes, nanoring etc. ZnO is a material whichexhibits piezoelectric and optoelectronic multiple properties. Especially for thelow-dimensional ZnO nanostructures, many useful effects can be detected due to thequantum confinements. Therefore, ZnO nanostructures have the promising potentialsin fabricating nano-optoelectronics and nano-electronics devices etc. The main workof this dissertation is based on the applications of ZnO nanostructures in the field ofresistive-switching random access memory and gas sensors devices. The dissentationis formed by the following aspects:1. The ZnO nanostructures and films were successfully synthesized by reactivevapor deposition method and radio frequency magnetron sputtering system,respectively. The low temperature （10K） PL spectra of the ZnO nanorods reveal thatthe nanorods have high quality as indicated by the negligible deep level emission. Thetemperature dependent PL spectra shows that the positions of the near band-edgeemission peaks show a redshift with increasing temperature and the intensity of D⁰Xdecreases with increasing temperature, whereas the free exciton becomes stronger andfinally becomes the dominated. The post annealing in oxygen ambient can improvethe crystalline quality and optical property of the ZnO films and presents the bestquality at the annealing temperature of700℃.2. Resistive-switching random access memory （RRAM） devices based onrandomly oriented nanowire networks （ZnO NWNs） was fabricated and researched.The Au/ZnO NWNs/ITO （MIM） structure was successfully fabricated, in which the ITO was played as both the substrate for growing ZnO and the bottom electrode forthe RRAM structure. The Au top electrode was deposited by thermal evaporationmethod using a metal shadow mask. I-V curves of the MIM structure results revealthe reproducible bipolar resistive property with a high R_on/R_offratio （¹0⁴）. Theswitching mechanism is confirmed in terms of the formation and rupture ofconductive filaments, with oxygen vacancies localized on the ZnO NWNs surfaceinvolved in.3. Physical type gas sensors operated by field ionization based on Pdnanoparticle-capped ZnO （Pd/ZnO） nanorods was fabricated and researched. Theresults show that the Pd/ZnO nanorod-based sensors, compared with the bare ZnOnanorod, have lower breakdown voltage for the detected gases with good sensitivityand selectivity. This precise breakdownvoltage is a fingerprinting property forindividual gas.更多还原