Bi-Sb-Te/金屬界面接觸電阻及接觸熱阻之量測與特性分析

Characterization of Electrical and Thermal Contact Resistances of Bi-Sb-Te/metal Interfaces

劉祐麟(Yu-Lin Liu)

指導教授 ： 廖建能

國立清華大學/工學院/材料科學工程學系/碩士(2012年)

摘要

銻化鉍系列化合物為目前室溫下熱電性質表現最佳的材料系統，且普遍應用於商用熱電致冷器模組中。而薄膜型熱電元件組裝中，熱電材料與金屬間所產生的額外接觸電阻與熱阻由於元件尺寸的縮小而不能忽略，這些阻抗將會造成熱電元件效能的低落。因此本研究的主題在於熱電材料與金屬接觸界面性質分析。在本研究中，熱電材料與金屬間接觸電阻率將以TLM(transmission-line-model)方法來量測，而接觸熱阻將以3ω法量測。本實驗成功建立量測系統並能得到可靠的量測數值。實驗結果得知Bi-Sb-Te/metal界面間的接觸電阻率約在10-5 ohm-cm2的數量級。而Bi-Sb-Te/metal界面間的接觸熱阻則為在約10-8 m2K/W的數量級。本研究將以不同的金屬界面來比較，藉由量測出的實驗數值來探討界面間電子與聲子的傳輸機制，以期對於熱電材料與金屬間的界面性質有更多的了解。最後由實驗值與理論值的分析，發現金屬的功函數與熱電材料的費米能量之間的差異會對接觸電阻率造成影響。

關鍵字

熱電薄膜 ； 接觸電阻 ； 接觸熱阻 ； TLM法 ； 3ω法

並列摘要

Bismuth telluride based compounds have been considered as promising candidates for thin-film thermoelectric (TE) devices due to their superior thermoelectric figure-of-merit at room temperature regime. Thermoelectrics/metal electrode junctions usually cause extra resistance to electron flow and heat flux in a typical TE module, and hence degrade the efficiency of TE devices. Such electrical/thermal contact resistance may become a performance killer, especially for thin-film TE devices. Thus, a methodology of evaluating the electrical/thermal contact resistance of TE/metal interfaces becomes essential. In this study the electrical and thermal contact resistances of Bi-Sb-Te thin film/metal were measured using the transmission-line-model (TLM) and the transient 3ω techniques, respectively. In this study, the results show that the electrical contact resistivities of Bi-Sb-Te/metals are in the order of 10-5 ohm-cm2 and the thermal contact resistances of the Bi-Sb-Te/metals are in the order of 10-8 m2K/W, respectively. The effects of Fermi energy of Bi-Sb-Te compounds and the work function of metals on the electrical and thermal contact resistances of Bi-Sb-Te film/metal interfaces are investigated.

並列關鍵字

thin-film thermoelectric ； electrical contact resistance ； thermal contact resistance ； transmission-line-model ； 3ω techniques

參考文獻

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