濺鍍三氧化鎢薄膜製作固態微型化二氧化碳感測元件之研究

Abstract

本論文的內容為以 RF 濺鍍方式,在白金微電極上鍍三氧化鎢薄膜,三氧化 鎢薄膜上再披覆一層固態電解質,做成固態､微型化､室溫下可工作的二 氧化碳感測器。微電極為本實驗室所研製之 Interdigitated 微電極,而 固態電解質由透明､可透氣體的聚乙烯醇和弱鹼性的碳酸氫鉀所組成,RF 濺鍍的三氧化鎢薄膜在微電極上有良好的附著力,有利於實驗的測量工作 。本元件的工作原理是藉著固態電解質在二氧化碳中會有酸化的現像,在 電解質內產生大量氫離子,而三氧化鎢在酸性環境中與氫離子反應還原成 HxWO3,由於HxWO3以之電阻遠小於WO3之電阻,我們可由測量三氧化鎢的電 阻變化來得知環境中二氧化碳的含量。元件經過測試後,室溫下對二氧化 碳有良好的重複性及可逆性,最快的反應時間約一分鐘,對純二氧化碳感測 電阻變化達94%,在二氧化碳感測上確實可發揮效用。 The thesis represents a carbon dioxide sensitive, solid micro- sensor with solid electrolyte covered sputt- ered tungsten oxide based on platinum microelectrodes in room temperature. The micro-electroeds manufactured is inter-digitated. The solid electrolyte is made by bicar- bonate contained,gas permeable transparent poly(vinyl alcohol). The strong adhesion of the sputtered tungsten oxide on micro-electrodes favors the experimentals. The solid electrolyte will be acidified when exposed to carbon dioxide.And the electrical characteristic (resistance) of tungsten oxide will dramatically change (be lower) resuling from being reduced to HxWO3 in acid electrolyte. Such that the concentration of carbon diox- ide in the atomsphere can be monitored through the mea- surement on resistance of tungsten oxide. The sensor can sense the carbon dioxide well in room temperature:the shortest response time is about 1 minute. 94% variation on resistance is detected when sensing pure carbon diox- ide. This sensor can absolutly work in sensing carbon dioxide gas.