AAO輔助生成一維氧化鋅奈米陣列之特性研究

Abstract

本研究以寬能帶(3.37eV)的二六族半導體氧化鋅(ZnO)為主要研究與探討目標；本實驗將重點著眼於一維方向成長的氧化鋅奈米結構， 亦即其它兩方向的尺寸限制在100nm以下。另外，陽極氧化鋁(AAO)結構提供許多優異的特性用於奈米研究上。因此，陽極氧化鋁提供可控制的一維方向孔洞陣列將是輔助成長奈米線的絕佳利器。 在本研究中，我們將針對AAO輔助生成一維氧化鋅奈米線陣列的低溫成長方法、化學以及電的特性加以研究探討。此外，我們試圖探討奈米線的幾何尺寸對於場發射特性的影響。在實驗中，我們利用低溫的水熱法成長氧化鋅奈米線，而陽極氧化鋁是由傳統的兩步驟陽極氧化法製備。 事實上，由實驗結果觀察知，奈米線的長寬比與其場發射特性是成正比關係；在實驗中，當奈米線的長寬比提升到53，我們得到優秀的場發射特性(β=6100)。最後，對於實驗結果，我發現一些缺點並且試圖推薦一些修正的可能方法；此外，我們也相信垂直的氧化鋅奈米線陣列在未來平面顯示器應用上將大有可為，且由水熱法提供的低溫製程對於可撓式光電與場發射元件的應用也是一大優勢。

ZnO is a wide band gap semiconductor (3.37ev) with a large exciton binding energy (60meV) at room temperature, and is one of the most important and versatile semiconductor materials. This research is focus on the one dimension nanostructure of ZnO which indicates the two directions were limited by the nano-scale (smaller than 100nm). The Anodic Aluminum Oxide (AAO) structure would provide some properties for nanotechnology study. Therefore, the AAO which could provide controllable one-dimensional pores was an excellent candidate to assistant fabrication of nanowires. The characteristics of the ZnO nanowires array by AAO assistance are paying attention in low temperature growth method, chemical and electric properties. Furthermore, we investigate influence on field emission by the geometry scale of nanowire. Here we report for ZnO nanowires growth using the hydrothermal method and AAO prepared by conventional two-step anodization. Actually, we observed the relation between aspect ratio and the field emitting enhancement factor β is in proportion. For example, the β is enhanced to 6100 which shows excellent field emission when the aspect ratio is 53. In summary, we observed some faults and recommended some improvements. Moreover, we believe that ZnO NWs array grow so vertical that it is a good candidate for the future flat panel display applications, and the hydrothermal method provides a low temperature process for fabricating flexible optoelectronic and field emission devices.