• 한국진공학회지
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• 제15권2호
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• pp.180-185
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• 2006

[ $Bi_{0.5}Sb_{1.5}Te_{3}/Bi_{2}Te_{2.4}Se_{0.6}$ ]계 박막형 열전발전 소자에 의해 volt 단위의 비교적 고전압에서 microwatt 수준의 출력을 발생시킬 수 있었다. 최대 출력은 온도차와 2차 함수적인 관계가 있었고, 주어진 온도차에서 판형 모듈의 적층수에 비례하여 증가하였다. 판형 모듈의 적층수와 직렬/병렬 연결 조합의 변화에 의해 출력 전압과 전류를 조절할 수 있었다. 온도차에 대한 개회로 전압과 폐회로 전류의 변화는 직선성을 보였다. 개회로 전압은 직렬 연결의 경우 판형 모듈의 수에 의존하였지만, 병렬 연결의 경우에는 의존하지 않았다. 반면, 폐회로 전류는 직렬연결의 경우 판형 모듈의 적층수와 무관하게 일정한 값을 나타내었고, 병렬 연결의 경우 판형 모듈의 적층수에 비례하여 증가하였다.

• 마이크로전자및패키징학회지
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• 제18권4호
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• pp.33-38
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• 2011

p형 $(Bi_{0.2}Sb_{0.8})_2Te_3$ 분말을 기계적 합금화 공정으로 제조하여 가압소결 후 가압소결온도에 따른 열전특성을 분석하였다. 가압소결온도를 $350^{\circ}C$에서 $550^{\circ}C$로 증가시킴에 따라 상온에서 측정한 Seebeck 계수가 237 ${\mu}V/K$에서 210 ${\mu}V/K$로 감소하고 전기비저항이 2.25 $m{\Omega}-cm$에서 1.34 $m{\Omega}-cm$로 감소하였으며, power factor가 $25.0{\times}10^{-4}W/m-K^2$에서 $32.9{\times}10^{-4}W/m-K^2$로 증가하였다. $350{\sim}550^{\circ}C$의 온도범위에서 가압소결한 시편들 중에서, $500^{\circ}C$에서 가압소결한 $(Bi_{0.2}Sb_{0.8})_2Te_3$ 가압소결체가 상온에서 1.09 및 $75^{\circ}C$에서 1.2의 가장 높은 무차원 성능지수를 나타내었다.

• 한국표면공학회지
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• 제49권1호
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.443-447
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• 2009

Bismuth-antimony-telluride based thermoelectric thin film materials were prepared by metal organic vapor phase deposition using trimethylbismuth, triethylantimony and diisopropyltelluride as metal organic sources. A planar type thermoelectric device has been fabricated using p-type $Bi_{0.4}Sb_{1.6}Te_3$ and n-type $Bi_{2}Te_{3}$ thin films. Firstly, the p-type thermoelectric element was patterned after growth of $5{\mu}m$ thickness of $Bi_{0.4}Sb_{1.6}Te_3$ layer. Again n-type $Bi_{2}Te_{3}$ film was grown onto the patterned p-type thermoelectric film and n-type strips are formed by using selective chemical etchant for $Bi_{2}Te_{3}$. The top electrical connector was formed by thermally deposited metal film. The generator consists of 20 pairs of p- and n-type legs. We demonstrate complex structures of different conduction types of thermoelectric element on same substrate by two separate runs of MOCVD with etch-stop layer and selective etchant for n-type thermoelectric material. Device performance was evaluated on a number of thermoelectric devices. To demonstrate power generation, one side of the device was heated by heating block and the voltage output was measured. The highest estimated power of 1.3 ${\mu}m$ is obtained at the temperature difference of 45 K.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.684-685
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• 2006

In the present study, the powder metallurgical fabrication of $Bi_{0.4}Te_3Sb_{1.6}$ thermoelectric materials has been studied with specific interest to control the microstructure by the mechanical grinding process. The $Bi_{0.4}Te_3Sb_{1.6}$ thermoelectric powders with a various particle size distribution were prepared by the combination of the mechanical milling and blending processes. The specific electric resistivity of the $Bi_{0.4}Te_3Sb_{1.6}$ sintered bodies mainly depended on the orientation of the crystal structure rather than the particle size of the raw powders.

• 한국재료학회지
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• 제6권7호
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• pp.678-683
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• 1996

In the fabrication processes of thin film thermoelectrics, a subsequent annealing treatment is inevitable to reduce the defects and residual stresses introduced during the film growth, and to make the uniform carrier concentration of the film. However, the diffusion-induced atomic redistribution and the broadening of p/n junction region are expected to affect the thermoelectric properties of thin film modules. The present study intends to investigate the diffusion at the p/n junctions of thermoelectric thin films and to relate it to the property changes. The film junctions of p-type(Bi0.5Sb1.5Te3)and n-type(Bi2Te2.4Se0.6)were prepared by the flash evaporation method. Aluminum thin layer was employed as a diffusion barrier between p-and n-type films of the junction. This was found to be an effective barrier by showing a negligible diffusion into both type films. After annealing treatment, the thermoelectric properties of p/n couples with aluminum barrier layer were accordingly retained their properties without any deterioration.

• 한국분말재료학회지
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• 제31권2호
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• pp.119-125
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• 2024

The n-type Bi_2-xSb_xTe₃ compounds have been of great interest due to its potential to achieve a high thermoelectric performance, comparable to that of p-type Bi_2-xSb_xTe₃. However, a comprehensive understanding on the thermoelectric properties remains lacking. Here, we investigate the thermoelectric transport properties and band characteristics of n-type Bi_2-xSb_xTe₃ (x = 0.1 - 1.1) based on experimental and theoretical considerations. We find that the higher power factor at lower Sb content results from the optimized balance between the density of state effective mass and nondegenerate mobility. Additionally, a higher carrier concentration at lower x suppresses bipolar conduction, thereby reducing thermal conductivity at elevated temperatures. Consequently, the highest zT of ~ 0.5 is observed at 450 K for x = 0.1 and, according to the single parabolic band model, it could be further improved by ~70 % through carrier concentration tuning.

• 한국분말재료학회지
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• 제23권2호
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• pp.120-125
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• 2016

P-type ternary $Bi_{0.5}Sb_{1.5}Te_3$ alloys are fabricated via mechanical alloying (MA) and spark plasma sintering (SPS). Different ball sizes are used in the MA process, and their effect on the microstructure; hardness, and thermoelectric properties of the p-type BiSbTe alloys are investigated. The phases of milled powders and bulks are identified using an X-ray diffraction technique. The morphology of milled powders and fracture surface of compacted samples are examined using scanning electron microscopy. The morphology, phase, and grain structures of the samples are not altered by the use of different ball sizes in the MA process. Measurements of the thermoelectric (TE) transport properties including the electrical conductivity, Seebeck coefficient, and power factor are measured at temperatures of 300-400 K for samples treated by SPS. The TE properties do not depend on the ball size used in the MA process.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.58.2-58
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• 2000

• 한국진공학회지
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• 제6권1호
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• pp.69-76
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• 1997

순간 증착법으로 $Bi_{0.5}Sb_{1.5}Te_3$(p형)와 $Bi_2Te_{2.4} Se_{0.6}$(n형) 박막을 제조하여 두께와 어닐 링 조건에 따른 Seebeck 계수, 전기전도도, carrier 농도 및 이동도, 열전도도, 성능지수의 변화 등 열-전기적 특성을 조사하였다. 473K에서, 1시간 진공 열처리한 결과 p형과 n형의 성능지구는 각각 $1.3{\times}10^{-3}K^{-1}$ 및 $0.3{\times}10^{-3}K^{-1}$으로 향상되었으며 두께에 크게 의존하지 않았 다. 이런 성질을 갖는 열전 박막을 소자화한 박막 온도 센서를 유리와 Teflon기판 위에 제 조하였으며, 이들의 온도 변화에 대한 열기전력, 민감도 및 시간 상수 등 센서 특성을 측정 하였다. p 및 n형의 leg 폭 1mm$\times$길이 16mm인 박막 온도 센서의 경우, Teflon 기판일 때 좋은 성능을 나타내었으며, 민감도는 2.91V/W, 시간 상수는 28.2초이었다.