一維奈米結構熱電量測元件之製作與應用

Fabrication of Microdevices for Investigating One-Dimensional Thermoelectric Properties

李宗勳(Tsung-Hsun Li)

指導教授 ： 李勝偉

國立中央大學/工學院/材料科學與工程研究所/碩士(2015年)

摘要

能源是現今最重要的問題之一，為了有效地利用能源，已經有很多研究在尋求更好的熱電轉換應用的新材料。熱電是熱和電之間的轉換，“熱電材料”用於描述那些擅長將熱轉換成電能的材料，通過熱電材料的熱電轉換效率，將廢熱轉換為電能，可以改善溫室氣體排放的問題，因此，熱電轉換元件可以解決當今面臨能源短缺的這一大問題。近年來，低維度半導體材料被證明是相當有潛力的熱電材料，為了研究一維熱電材料性質，我們製作出懸浮的熱電感測元件以及利用無電鍍金屬輔助蝕刻合成出一般及重摻雜的矽單晶奈米線，奈米線以顯微操作的方式放置於元件上，量測之後發現，有大量孔隙的重摻雜矽奈米線比起輕摻雜奈米線具有較低的熱導與席貝克常數，導致較高的熱電優質。因此，我們嘗試以表面粗糙度和矽奈米線的孔隙率來解釋這些結果是因金屬輔助化學蝕刻過程所引起的。

關鍵字

矽 ； 一維奈米結構 ； 熱電量測元件 ； 微影製程

並列摘要

Energy is one of the most important issues today. For efficient use of energy, there has been much research in the search for new materials for advanced thermoelectric energy conversion applications. Thermoelectricity is the conversion between heat and electricity. “Thermoelectric (TE) materials” is used to describe the materials that are good at converting heat to electricity. By converting waste heat into electricity through the thermoelectric power of thermoelectric materials without producing greenhouse gas emissions, thermoelectric generators can be an important part of the solution to today’s energy challenge. In recent years, low-dimensional materials of semiconductor have been proved to be potential as thermoelectric materials. In order to experimentally investigate the TE properties in one-dimensional materials in a systematic manner, it is necessary to measure the TE parameters of samples with precisely controlled dimensions. For this purpose, we batch-fabricated suspended micro-fabricated devices for measuring thermal and electrical transport in lightly- and heavily-doped Si nanowires (SiNWs) prepared using metal-assisted chemical etching. The resulting nanowire is placed on a micro-fabricated device by micro-manipulation. We found that the heavily-doped SiNW has lower thermal conductivity and Seebeck coefficient than lightly- doped SiNW, resulting in higher ZT values. We attempt to explain these results in terms of surface roughness and porosities of SiNW caused during the metal-assisted chemical etching.

並列關鍵字

silicon ； one-dimensional nanostructures ； thermoelectric device ； lithography

參考文獻

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