（毕业设计论文）《Co、Ni掺杂ZnO半导体材料及其气敏性能的研究》.doc

PAGE Co、Ni掺杂ZnO半导体材料及其气敏性能的研究 摘要 半导体气体传感器因其具有结构简单，成本低廉，灵敏度高，工艺成熟等优点，被广泛用于可燃性气体、有毒气体的检漏报警，以及环境气体的监控等领域。ZnO是传统的半导体气敏材料。 本文采用溶胶凝胶法制备纯ZnO、Co掺杂ZnO和Ni掺杂ZnO纳米棒阵列。用X 射线衍射仪和扫描电镜对产物的结构和微观形貌进行了表征。通过对气体的灵敏度、响应时间和恢复时间的测量评价了ZnO纳米棒阵列的气敏性能，并对ZnO的气敏机理进行了论述。 扫描电镜结果表明所得到的ZnO纳米棒阵列分布均匀，属于六方晶系，晶体结构为纤锌矿结构。X射线衍射结果表明Co2+和Ni2+随机替代Zn2+位置进入ZnO晶格，Co掺杂ZnO和Ni掺杂ZnO纳米棒阵列比纯ZnO纳米棒阵列有更好的（002）峰取向。对乙醇的气敏性能测试表明，工作温度为250℃时，随着气体浓度的增加，样品的电阻逐渐减小，对乙醇的灵敏度逐渐增大。在同一气体浓度，随着Co和Ni掺杂量的增加，样品对乙醇的灵敏度逐渐增大。并且响应时间和恢复时间均小于10秒。总体来说，掺杂后的ZnO纳米棒阵列气敏元件与纯ZnO纳米棒阵列气敏元件相比有更高的灵敏度，更快的响应时间和恢复时间。 实验表明，掺杂使纳米ZnO薄膜的结构得到改善，有效地降低了纳米ZnO薄膜的电阻，同时薄膜的气敏性能也得到较大的改善。 关键词：ZnO 溶胶凝胶法 Co掺杂 Ni掺杂 纳米棒阵列 气敏性能 Investigation on gas sensing property of Co doped and Ni doped ZnO semiconductor material ABSTRACT Semiconductor gas sensors, which have simple structure, low cost, high sensitivity and mature fabricating technique, are now widely employed in detection of toxic and inflammable gases and metering of atmospheric gases. ZnO is the conventional semiconductor gas sensing material. In this paper, pure ZnO, Co doped ZnO and Ni doped ZnO nanorod arrays are prepared by a sol-gel method. Their structure and morphology are characterized by XRD and SEM analyses. The corresponding gas sensing properties are investigated by measuring the sensitivity, response and recovery time. And the reason of the gas sensing emission of ZnO is discussed. SEM micrographs show that well-aligned ZnO nanorods can be obtained, the as-prepared ZnO nanorods belong to Hexagonal System and they are crystallized in the wurtzite phase. XRD patterns show that Co2+ ions and Ni2+ ions have substituted the Zn2+ ions into ZnO lattice. Co doped and Ni doped ZnO nanorod arrays exhibit better (002) orientation than pure ZnO. Sensitivity measurement of ethanol show that at the temperature of 250℃, the resistance decrease and the gas sensitivities to ethanol increase with the increase of gas concentration. In the same gas concentration, the gas sensitivities to ethanol increase with the incr