熱效應與表面帶電分子吸附改變蕭特基能障之研究

Study on the Schottky barrier height varies in the thermal and the charged molecules adsorption effect

李昀儒(Yun-Ju Lee)

指導教授 ： 葉炳宏

淡江大學/理學院/物理學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00336

摘要

本論文提出一新穎氣體感測機制，其原理在於利用奈米線之高表面積-體積比，搭配金屬與半導體間之蕭特基接觸，達到對氣體之超高感測靈敏度。載子在蕭特基接面間之傳輸主要受蕭特基能障高度之影響，而蕭特基能障容易受到熱效應與表面帶電分子吸附影響，因此本論文深入探討蕭特基能障受熱效應與帶電分子吸附而改變之機制。
本實驗結果顯示：在熱效應部分，隨著元件操作溫度之提升，蕭特基元件之基本電性將由蕭特基接觸之整流特性轉變為歐姆接觸之非整流特性，此因高溫提高載子之能量而輕易越過蕭特機能障；而在帶電分子吸附部分：氧化鋅奈米線/鉑接面之蕭特基能障會因帶電分子之吸附而變化。實驗結果亦顯示元件之感測靈敏度取決於蕭特基能障之變化程度。本研究之實驗結果顯示，奈米蕭特基接觸元件，對氧氣與一氧化碳的檢測能力分別為3,250% 與 32,000%，此結果相對傳統奈米元件之檢測能力可說大幅提昇。

關鍵字

奈米線 ； 奈米元件 ； 氣體感測 ； 氧化鋅 ； 一氧化碳 ； 蕭 特基接觸 ； 蕭特基能障

並列摘要

We has demonstrated a new gas detection methodology based on Schottky contacted (matel/semiconductor interface) using zinc oxide nanowire. Using the Schottky barrier height as a gate to control the current signal passing, which is sensitive effected by temperature variation and charged molecules adsorption. By the operative temperature changing and the different gas conditions sensing of Schottky contacted device, the mechanism of Schottky barrier height varied by thermal effect and charged molecules adsorption has been reported has been achieved, respectively.
First of all, the Schottky contacted device exhibited Ohmic characteristic under high temperature condition(above 200℃) due to high carrier energy which allowed carriers pass through the Schottky barrier easily. Secondly, the Schottky barrier height was varied when different molecules absorbed on the ZnO/Pt interface. Thirdly, the Schottky barrier height variations can be used as a high sensitive gas sensor nanodevice. By using the novel gas nanodevice, ultrahigh sensitivities of 3,250% and 32,000% for oxygen and carbon monoxide sensing, respectively.

並列關鍵字

nanowire ； nanodevice ； gas sensor ； nanosensor ； Schottky contact ； Schottky barrier ； ideality factor ； ZnO ； carbon monoxide

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