鈷擴散阻障層對碲化鍺熱電模組性質與 界面穩定度影響之研究;Effect of Cobalt Diffusion Barrier on Thermoelectric Property of GeTe Thermoelectric Joint for Enhanced Performance and Thermal Stability

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Title:	鈷擴散阻障層對碲化鍺熱電模組性質與界面穩定度影響之研究;Effect of Cobalt Diffusion Barrier on Thermoelectric Property of GeTe Thermoelectric Joint for Enhanced Performance and Thermal Stability
Authors:	龔成浩;Kung, Cheng-Hao
Contributors:	化學工程與材料工程學系
Keywords:	熱電塊材;熱電性質;擴散阻障層;鍺碲基;菱面體結構;交互擴散;Thermoelectric bulk material;Thermoelectric property;Diffusion barrier;GeTe;Rhombohedral structure;Interdiffusion
Date:	2024-09-12
Issue Date:	2024-10-09 15:31:22 (UTC+8)
Publisher:	國立中央大學
Abstract:	在面對全球性氣候暖化危機的迫切需要下，實現淨零碳排放和碳中和已成為一項全球性的共同目標。不排放污染、結構簡單以及能夠將來自自然界、工業和汽車的廢熱轉換為電能的特點使得熱電發電裝置成為一項具有前景的技術。對於中溫區間段(200-500 oC)塊材熱電模組來說，高溫導致的原子擴散將影響模組的性能。本研究旨在發現加入鈷（Co）擴散屏障層能增強p型GeTe塊材的熱電性能，並探討影響模組性能的界面反應，因為模組內熱電材料跟電極之間的穩定連接對於確保熱電裝置的可靠性至關重要。透過分析GeTe的晶體結構及熱電性值的結果，表現出在添加Co擴散阻障層後GeTe的熱電效能（zT）值顯著增加。藉由電子微探儀（EPMA）分析，發現Co會朝GeTe擴散並反應出Co-Te界金屬化合物。在經歷了長時間熱處理測試後，銅電極與GeTe之間的界面接觸電阻有明顯增加。將Co阻障層電鍍到GeTe再經過長期熱處理後，電導率有所提高但材料的熱導率卻降低，發生這樣的改變是因為Co原子已經擴散到GeTe晶格中的空缺位置，造成聲子散射從而影響到熱導率。最後從結果發現添加Co阻障層並不會降低zT值，相反地電鍍Co阻障層能使p型GeTe的zT值增加56%。此外本研究強調的是探討GeTe zT值的提升，而不是追求極高的峰值。;Achieving net zero carbon emissions and carbon neutrality has emerged as a global imperative in addressing the climate crisis. The qualities like no emission pollution, simple structure, and the ability to convert waste heat generated from nature, industry, and automobiles into electrical energy make thermoelectric power generation devices a promising technology. For mid-temperature bulk thermoelectric modules, the diffusion of atoms induced by higher temperature will affects the module’s performance. This study investigates the influence on thermoelectric properties of p-type GeTe after integrating cobalt (Co) diffusion barrier and focuses on the interfacial reactions in GeTe joint that degrade thermoelectric performance. It is essential to establish stable interconnections in the joint for ensuring the reliability of the device. The research highlights the significantly increased the figure of merit (zT) values of GeTe after adding of Co diffusion barrier by examining its improved thermoelectric properties. The diffusion of Co into GeTe and the formation of Co-Te intermetallic compounds were revealed through EPMA analysis. There is a substantial increase in contact resistivity of the GeTe joint after aging. However, electrical conductivity improves and thermal conductivity decreases after depositing Co and subjecting it to long-term aging. This improvement occurs because the Co atoms, which have diffused into the GeTe lattice, occupy vacancy sites. Instead of degrading the zT value, Co deposition leads to a 56% increase in the zT value for the p-type GeTe joint. This study emphasizes the improvement of the zT value rather than pursuing a high peak zT value for GeTe.
Appears in Collections:	[化學工程與材料工程研究所] 博碩士論文

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