WATLab and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L3G1, Canada.
ACS Appl Mater Interfaces. 2009 Apr;1(4):789-96. doi: 10.1021/am800220v.
A simple and direct electrodeposition technique is employed to fabricate ZnO nanospikes and nanopillars on indium-tin oxide glass substrates at 70 degrees C without using any template, catalyst, or seed layer. Both ZnO nanospikes and nanopillars exhibit highly crystalline ZnO wurtzite structure with a preferred (0001) plane orientation in their high-resolution transmission electron microscopic images and X-ray diffraction patterns. The corresponding Raman spectra provide evidence for the presence of defects and oxygen vacancies in these nanostructures, which could produce the photoluminescence observed in the visible region. X-ray photoelectron spectroscopy further indicates the presence of a Zn(OH)2-rich surface region in these ZnO nanostructures and that a higher Zn(OH)2 surface moiety is found for nanospikes than nanopillars. In contrast to the nanopillars with flat tops, the nanospikes with tapered tips of 20-50 nm diameter provide a favorable geometry to facilitate excellent field-emission performance, with a low turn-on electric field of 3.2 V/microm for 1.0 microA/cm(2) and a threshold field of 6.6 V/microm for 1.0 mA/cm(2). The superior field-emission property makes the nanospikes among the best ZnO field emitters fabricated on a glass substrate at low temperature.
采用简单直接的电沉积技术,在 70°C 下于氧化铟锡玻璃衬底上无需使用任何模板、催化剂或种子层制备 ZnO 纳米刺和纳米柱。在高分辨率透射电子显微镜图像和 X 射线衍射图谱中,两种 ZnO 纳米刺和纳米柱均表现出高度结晶的 ZnO 纤锌矿结构,具有优先的(0001)平面取向。相应的拉曼光谱为这些纳米结构中存在缺陷和氧空位提供了证据,这些缺陷和氧空位可能产生在可见光区域观察到的光致发光。X 射线光电子能谱进一步表明,这些 ZnO 纳米结构中存在富含 Zn(OH)2 的表面区域,而且纳米刺中 Zn(OH)2 的表面部分比纳米柱中更多。与具有平顶的纳米柱不同,具有 20-50nm 直径的锥形尖端的纳米刺提供了有利于优异场发射性能的有利几何形状,在 1.0μA/cm(2)时开启电场为 3.2V/μm,在 1.0mA/cm(2)时阈值电场为 6.6V/μm。优越的场发射性能使得纳米刺成为在低温下在玻璃衬底上制备的最佳 ZnO 场发射器之一。