摘要
运用气相沉积方法分别在硅片表面和钨针尖上制备了非取向生长的ZnO纳米线,并通过场发射显微镜研究了纳米线样品的平面场发射特性和针尖场发射特性.结果显示,非取向生长的ZnO纳米线薄膜场发射的开启电压和阈值电压所对应的场强分别为4.7和7.6V/μm,场增强因子达103量级,具有较阵列生长的ZnO纳米线更为优异的场发射能力.非取向生长ZnO纳米线薄膜场发射能力的增强归因于其所具有的稀疏结构避免了强场作用下屏蔽效应的产生,有效地提高了薄膜场发射的电流密度.将ZnO纳米线组装在钨针尖上能够明显地改善针尖的场发射性能,在超高分辨显微探针领域具有良好应用前景.
Unoriented ZnO nanowires are fabricated either on the surface of silicon wafer or at the tip of needle-like tungsten by vapor-phase deposition. Both the plane field emission and tip field emission of ZnO nanowires are studied using a field emission microscope. The results show that for unoriented ZnO nanowire thin films,the electric field intensities corresponding to the turn-on voltage and threshold voltage of field emission are 4.7 and 7. 6V/μm,which are much lower than those of aligned nanowire arrays. The enhancement of the field emission ability is attributed to the fact that the field-induced screening effect can be effectively avoided due to the widely spaced intervals that exist between the unoriented nanowires. The field emission of the tungsten tip also can be effectively improved by assembling ZnO nanowires on the tip,which presents a potential application of ZnO nanowire on the probe of electron microscopes with ultrahigh resolution.
基金
国家重点基础研究发展规划(批准号:2001CB610503)
国家自然科学基金(批准号:50202002
60471007
60231010
90206048)
北京市自然科学基金(批准号:4032012
4042017)资助项目~~
关键词
ZNO
纳米线
气相沉积
场发射
ZnO
nanowire
vapor-phase deposition
field emission
