• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.859-860
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• 2011

• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.9-16
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• 2017

Thermoelectric power generation (TEG) technology with high figure of merit (ZT) has become the need of the modern world. TEG is a potent technology which can tackle most of the environmental issues such as global warming, change in climatic conditions over the globe, and for burning out of various resources of non-renewable energy like as petroleum deposits and gasolines. Although thermoelectric materials generally convert the heat energy from wastes to electricity according to the theories Seebeck and Peltier effects yet they have not been fully exploited to realize their potential. Researchers are focusing mainly on how to improve the current ZT value from 1 to 2 or even 3 by various approaches. However, a higher ZT value is found to be difficult due to complex thermoelectric properties of materials. Hence, there is a need for developing materials with high figure of merit. Recently, various nanotechnological approaches have been incorporated to improve the thermoelectric properties of materials. In this review paper, the authors have performed a thorough literature survey of various kinds of TEG technology.

• 정보저장시스템학회논문집
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• 제10권2호
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• pp.32-38
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• 2014

Heat emission from the laser diode used in the optical disc drive and the defects from the increased temperature at the system have attracted attentions from the field of the information storage device. Thermoelectric refrigerator is one of the fine solutions to solve these thermal problems. The refrigeration performance of thermoelectric device is dependent on the thermoelectric material's figure-of-merit. Meanwhile, high electrical contact resistivity between metal electrode and p- and n-type thermoelectric materials in the device would lead increased total electrical resistance resulting in the degeneracy in performance. This paper represents the manufacturing process of the PbTe-based material which has one of the highest figure-of-merit at medium-high-temperature, ~ 600K to 900 K, and the nickel contact layer for reduced electrical contact resistance at once, and the results showing the decent contact structure and figure-of-merit even after the long-term operation environment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.175-180
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• 2008

Thermoelectric materials convert temperature difference to electric power for power generation and vice versa for refrigeration. Recent advances in enhancing the thermoelectric figure-of-merit shed light on efficient power generation from the waste heat available in industries and vehicles. Nanoscale phenomena with both nanoscale constituent-embedded bulk samples and nanoscale materials proving enhanced thermoelectric performance have been widely reviewed. Bulk materials of crystal-orientation and nano-structured particle embedding seem to promise a higher thermoelectric figure-of-merit and an effective power generation application. As a preliminary study, Si-Ge nanocomposite was prepared with spark plasma sintering method and its properties were examined.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.682-683
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• 2006

Thermoelectric conversion efficiency of thermoelectric elements can be increased by using a structure combining n-type and p-type semiconductors. From the above point of view, attention was directed at ZnO as a candidate n-type semiconductor material and investigations were made. As the result, a dimensionless figure of merit ZT close to 0.28 (1073K) was obtained for specimens produced by the PCS (Pulse Current Sintering) method with addition of specified quantities of $TiO_2$, CoO, and $Al_2O_3$ to ZnO. It was found that the interstitial $TiO_2$ in the ZnO restrains the grain growth and CoO acts onto the bond between grains. The influence of the inclusion of $TiO_2$ and CoO onto the sintering behavior also was investigated.

• 마이크로전자및패키징학회지
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• 제20권1호
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• pp.15-19
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• 2013

용해/분쇄법으로 제조한 n형 $Bi_2(Te_{0.9}Se_{0.1})_3$ 분말에 0.5 vol% $TiO_2$ 나노분말을 분산시켜 가압소결 후, $TiO_2$ 나노분말의 분산이 $Bi_2(Te_{0.9}Se_{0.1})_3$ 가압소결체의 열전특성에 미치는 영향을 분석하였다. $Bi_2(Te_{0.9}Se_{0.1})_3$ 가압소결체는 $2.93{\times}10^{-3}/K$의 최대 성능지수 및 1.02의 최대 무차원 성능지수의 우수한 열전특성을 나타내었다. 0.5 vol% $TiO_2$ 나노분말의 첨가에 의해 $Bi_2(Te_{0.9}Se_{0.1})_3$ 가압소결체의 최대 성능지수가 $2.09{\times}10^{-3}/K$로 감소하였으며, 최대 무차원 성능지수는 0.68로 저하하였다.

• Electronic Materials Letters
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• 제14권6호
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• pp.725-732
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• 2018

The thermoelectric and transport properties of Ti-doped FeVSb half-Heusler alloys were studied in this study. $FeV_{1-x}Ti_xSb$ (0.1 < x < 0.5) half-Heusler alloys were synthesized by mechanical alloying process and subsequent vacuum hot pressing. After vacuum hot pressing, a near singe phase with a small fraction of second phase was obtained in this experiment. Investigation of microstructure revealed that both grain and particle sizes were decreased on doping which would influence on thermal conductivity. No foreign elements pick up from the vial was seen during milling process. Thermoelectric properties were investigated as a function of temperature and doping level. The absolute value of Seebeck coefficient showed transition from negative to positive with increasing doping concentrations ($x{\geq}0.3$). Electrical conductivity, Seebeck coefficient and power factor increased with the increasing amount of Ti contents. The lattice thermal conductivity decreased considerably, possibly due to the mass disorder and grain boundary scattering. All of these turned out to increase in power factor significantly. As a result, the thermoelectric figure of merit increased comprehensively with Ti doping for this experiment, resulting in maximum thermoelectric figure of merit for $FeV_{0.7}Ti_{0.3}Sb$ at 658 K.

• 한국재료학회지
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• 제21권8호
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• pp.456-460
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• 2011

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.

• 한국재료학회지
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• 제9권5호
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• pp.520-527
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• 1999

열전 소결재 제조의 새로운 시도로, 분말의 압출과 소결을 동시에 할 수 있는 공정에 대하여 연구하였다. $(Bi,Sb)_2(Te,Se)_3$계 압출-소결재를 제조함에 있어 제조 변수를 적절히 조절하여 건전한 표면과 미세조직을 갖는 고밀도의 소결재를 얻을 수 있었다. p형 재료의 경우 Te 도핑량이 증가함에 따라 Seebeck 계수가 증가하였으며 3 at% Te을 첨가한 경우 상온에서의 열전 성능 지수가 $2.5\times10^{-3}/K$를 나타내었다. 한편 n형 재료의 경우 0.16 mol% $SbI_3$를 도핑한 시편에서 $1.8\times10^{-3}/K$의 열전 성능지수를 보였다. p형 및 n형 재료 모두 압출 방향에 수직한 방향보다 평행한 방향으로의 운반자 이동도와 열전 성능지수가 높게 나타났다.

• Journal of Ceramic Processing Research
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• 제20권6호
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• pp.582-588
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• 2019

FeVSb1-xTex (0.02 ≤ x ≤ 0.10) half-Heusler alloys were fabricated by mechanical alloying process and subsequent vacuum hot pressing. Near single half-Heusler phases are formed in vacuum hot pressed samples but a second phase of FeSb2 couldn't be avoided. After doping, the lattice thermal conductivity in the system was shown to decrease with increasing Te concentration and with increasing temperature. The lowest thermal conductivity was achieved for FeVSb0.94Te0.06 sample at about 657 K. This considerable reduction of thermal conductivities is attributed to the increased phonon scattering enhanced by defect structure, which is formed by doping of Te at Sb site. The phonon scattering might also increase at grain boundaries due to the formation of fine grain structure. The Seebeck coefficient increased considerably as well, consequently optimizing the thermoelectric figure of merit to a peak value of ~0.24 for FeVSb0.94Te0.06. Thermoelectric properties of various Te concentrations were investigated in the temperature range of around 300~973 K.