以水熱法成長氧化鋅奈米柱之紫外光激發室溫氣體感測器

Abstract

本研究成功地以水熱法結合指叉電極製備了偵測揮發性有機化合物氣體的感測晶片，主要的優勢在於製作成本低廉且製程簡便，以氧化鋅作為感測材料，並針對此種材料特性，以紫外光進行激發增加氣體感測訊號。 實驗方法以濺鍍方式濺鍍氧化鋅種子層，並以六甲基四胺與醋酸鋅調配水熱法使用之水溶液，以烘箱進行恆溫水熱法，透過使用UV光照射晶種層進行前處理可使晶種層輔助奈米柱軸向成長效果提升，與未進行UV光前處理比較使奈米柱形貌由花型成長為柱型結構，並搭配改變反應時間與高溫退火前處理，可改變氧化鋅奈米柱的成長結果。特性分析的量測使用掃描式電子顯微鏡(SEM)觀察奈米柱的尺寸。 透過奈米結構使材料的光吸收增加進而提升了UV光增益的效果，也能有效增加氣體接觸面積。此氧化鋅感測薄膜具有良好的氣體響應，且此結構所反映出的訊號亦與濃度之間有線性關係。有別以往製備奈米感測薄膜的製程，本研究製程相對簡單，並成功地將此技術與氣體感測結合，製備出高感測效果的氣體吸附感測薄膜。

In this research, a novel volatile organic compound (VOC) sensing layer was fabricated. The advantage of the fabrication is the low cost and the simple equipment. We use the Zinc Oxide (ZnO) as the sensing material to detect the reduction gas. By the characteristic of oxidation of the surface of ZnO, the oxygen ion will become reduction when the surface is in the environment with volatile organic compound. ZnO seed layers were deposited by RF Sputter. ZnO nanowires were grown in aqueous of zinc acetate and hexamethylenetetramine. With UV pretreatment, ZnO nanowires change from flower-like to well-aligned and vertical growth nanowires. The different nanowires morphologies can be fabricated by different growth time and high temperature annealing. The ZnO films were characterized by field-emission scanning electron microscopy (FE-SEM) to illustrate the morphologies. The signal of the nanowires structure was linear with the different concentration. The nanowires structure not only enhances light absorption but also the gas sensing results. On the other hand, we use the hydrothermal method to fabricate nanowires on the metallic interdigitated electrodes and apply this technology to gas sensing area successfully.