Full metadata record
DC Field | Value | Language |
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dc.contributor.advisor | Kwon, Yong Seung | - |
dc.contributor.author | Cho, Hyun Yong | - |
dc.date.accessioned | 2017-05-10T08:51:26Z | - |
dc.date.available | 2017-01-02T00:00:00Z | - |
dc.date.issued | 2015 | - |
dc.identifier.uri | http://dgist.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000001916045 | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.11750/1398 | - |
dc.description.abstract | Pb-based materials, which are superior for thermoelectric performance, environmentally have toxicity. Thus the materials should be alternated by non-toxic materials. Tin telluride (SnTe) is isostructural with PbTe and PbSe which are rock salt structure. In addition, SnTe is similar to the electronic band structure (two valence band system) with PbTe and PbSe. Thus, SnTe, which is overcome by low Seebeck coefficient and by large thermal conductivity, can be expected by good thermoelectric material. Thus, Ag-included poly crystals Sn1-xAgxTe (x=0.1, 0.2, 0.3, and 0.4) were prepared by box furnace and by hot press to confirm thermoelectric performance of the samples. By accident, we noticed difference that XRD patterns of Sn1-xAgxTe are changed from two phases (SnTe, AgTe) to mixed phase (SnTe/AgTe) before hot pressing and after. In addition, electrical conductivity of samples is maintained until high temperature. The power factor of sample to include silver(x=0.1) has maximum value (1.1 mW/mK2) at 673K. However, SnTe has higher power factor than Ag-included SnTe. Nevertheless, we can carefully expect that sample to include mixed phase obtain high electrical conductivity. Exceptionally, we developed the measurement of the thermoelectric power in the temperature range from 2K to 300K. By using two heaters, two thermometer, chip resistors, et al, measurement equipment is fabricated exactly. In addition, high density data is obtained by two heaters that are operated by turn. The system is controlled by LabVIEW software. In order to demonstrate this system, reference data of Pt wire and Ca10Nax(Pt3As8)(Fe2As2)5 superconductor were calibrated by developed equipment. Therefore we demonstrated the equipment with superior performance through confirming calculated data. ⓒ 2015 DGIST |
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dc.description.tableofcontents | Chapter 1. Introduction 1-- 1.1 Thermoelectric effect 1-- 1.2 Figure of merit (ZT) & Efficiency 2-- 1.3 Carrier concentration 4-- 1.4 Sn1-xAgxTe 5-- Chapter 2. Theory 9-- 2.1 Seebeck effect 9-- 2.2 Effects of charge carrier’s interactions on Seebeck coefficients 11-- 2.3 Thermal conductivity 13-- Chapter 3. Seebeck coefficient measuring equipment 15-- 3.1 Experimental setup 16-- 3.2 Operating principles 17-- 3.3 Calculation of sample Seebeck coefficient 18-- Chapter 4. Thermoelectric property of Sn1-xAgxTe 20-- 4.1 Experimental Methods 20-- 4.1.1 Sample preparation 20-- 4.1.2 Seebeck coefficient, Electrical conductivity measurement 22-- 4.2 Results and Discussion 23-- 4.2.1 X-Ray Diffraction 23-- 4.2.2 Scanning electron microscopy and Energy Dispersive Spectroscopy 26-- 4.2.3 Seebeck coefficient 28-- 4.2.4 Electrical conductivity 29-- 4.2.5 Power factor 30-- Chapter 5. Conclusion 31-- References 33-- Summary (in Korean) 35 |
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dc.format.extent | 35 | - |
dc.language | eng | - |
dc.publisher | DGIST | - |
dc.subject | SnTe | - |
dc.subject | mixed phase | - |
dc.subject | electrical conductivity | - |
dc.subject | Seebeck coefficient | - |
dc.subject | power factor | - |
dc.subject | 섞인 상태 | - |
dc.subject | 전기전도도 | - |
dc.subject | 제백상수 | - |
dc.subject | 파워팩터 | - |
dc.title | Fabrication of Seebeck coefficient measurement system and thermoelectric properties in Sn1-xAgxTe compounds | - |
dc.type | Thesis | - |
dc.identifier.doi | 10.22677/thesis.1916045 | - |
dc.description.alternativeAbstract | 열전 성능이 우수한 Pb-based 물질은 환경적으로 독성을 가진다. 따라서 Pb-based 물질은 독성이 없는 물질로 대체 되어야 한다. Tin telluride (SnTe) 는 PbTe, PbSe 와 같은 rock salt 구조 이다. 게다가 SnTe 는 PbTe, PbSe 의 전자 밴드 구조 (두 개 밴드 구조)와 유사한 밴드구조를 가졌다. 따라서 작은 제백상수와 큰 열전도도를 극복한 SnTe 좋은 열전재료가 될 것으로 기대된다. 그래서 실버가 포함된 poly crystals 이 박스 퍼니스와 핫프레스에 의해 준비되었다. 우연적으로 우리는 Sn1-xAgxTe 의 XRD 패턴이 핫프레스 전후에 바뀌는 것을 알았다. 그리고 핫프레스 전에는 두개의 사에서 후에는 섞인 패턴이 발견 되었다. 게다가 섞인 패턴 때문에 샘플들의 전기전도도는 높은 온도까지 잘 유지했다. 파워팩터는 실버(x=1)에서 가장 높은 값 (1.1 mW/mK2 ) 을 673K 에서 가졌다. 그러나 parent SnTe 는 실버가 포함된 시료보다 높은 파워팩터를 가졌다. 그럼에도 불구하고, 우리는 샘플이 상이 섞인 상태에서 높은 전기전도도를 가진다고 조심스럽게 예측 해볼 수 있다. 예외적으로 우리는 2K-300K 까지 측정할 수 있는 열전측정 장비를 개발했다. 장비는 두 개의 히터, 두 개 온도계, 칩 저항, 등으로 이루어져있다. 게다가 두 개의 히터가 번갈아 가면서 작동하기 때문에 높은 밀도의 데이터를 얻을 수 있다. 이 시스템은 랩뷰 소프트웨어에 의해 조작된다. 측정 장비를 증명하기 위해 우리는 Pt wire 의 참고 데이터와 실험과 비교하였고, 초전도체인 Ca10Nax(Pt3As8)(Fe2As2)5 으로 비교함으로써 우수한 성능을 확인하였다. ⓒ 2015 DGIST |
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dc.description.degree | Master | - |
dc.contributor.department | Emerging materials Science | - |
dc.contributor.coadvisor | Kim, Dong Hwan | - |
dc.date.awarded | 2015. 2 | - |
dc.publisher.location | Daegu | - |
dc.description.database | dCollection | - |
dc.date.accepted | 2015-01-12 | - |
dc.contributor.alternativeDepartment | 대학원 신물질과학전공 | - |
dc.contributor.affiliatedAuthor | Cho, Hyun Yong | - |
dc.contributor.affiliatedAuthor | Kwon, Yong Seung | - |
dc.contributor.affiliatedAuthor | Kim, Dong Hwan | - |
dc.contributor.alternativeName | 조현용 | - |
dc.contributor.alternativeName | 권용성 | - |
dc.contributor.alternativeName | 김동환 | - |