• Korean Journal of Materials Research
• /
• v.9 no.5
• /
• pp.520-527
• /
• 1999

As a new approache(extrusion-sintering process) to fabricate the thermoelectric materials, it has been at tempted to extrude and sinter the powders simultaneously. It was possible to produce the highly dense <$(Bi,Sb)_2(Te,Se)_3$-based thermoelectrics with sound surface appearances and microstructures by adjusting the process variables. For the p-type materials, the Seeback coefficient was increased with the amount of Te dopants, and the thermoelectric figure of merit appeared to be $2.5\times10^{-3}/K$ at room temperature when doped with 3 at % Te. The n-type specimen doped with 0.16 mol% $SbI_3$ showed the thermoelectric figure of merit of $1.8\times10^{-3}/K$. In both p-type an 우-type materials, the carrier mobility an the thermoelectric figure of merit parallel to the extrusion direction were higher than those perpendicular to it.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.207-209
• /
• 1987

This paper reports the effect of additive elements such as Bi, Sb on degradation and hole formation of the Te-Se thin films. Changes in light transmission were used to monitor the degradation rate of thin Te films in an accelerated temperature-humidity environment. In thin accelerated temperature-humidity environment, $(Te_{86}Se_{14})_{70}Bi_{30}$ thin film was stable and $(Te_{86}Se_{14})_{50}Sb_{50}$ thin film was unstable in comparison with the other films that used in this experiment. The hole formation was carried out in the Te-based thin films.

• Journal of the Korean Vacuum Society
• /
• v.15 no.4
• /
• pp.367-373
• /
• 2006

We have observed a large increase in the magnetoresistance (MR) of Bi thin films, which were subjected to a post-annealing procedure at $268^{\circ}C$C, $3^{\circ}C$ below the Bi melting point. We have achieved an increase in the MR by 260-fold and 1200-fold at 5 K and 5 T after post-annealing, as compared with 190 and 620 for an as-deposited Bi film on PbTe/CdTe(111) and on mica, respectively. The large MR increase by post-annealing might be due to the improvement of crystallinity according to the x-ray analysis. However, post-annealing over a certain amount time showed the reduction in MR values.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.5 no.3
• /
• pp.1-8
• /
• 1968

This thermcelectrie generator devices have been determined for bismuth alloys, Sb2T and AnSb containing small amounts of doping materials. The thermoeleotric matermoelectric power;$\alpha$; resistivity; $\rho$, heatconduction; k, and temperature difference between cold and hot junction was measured. Generator consisting both B T + B S and B T+S T is better efficient than others containing another thermoceuple matarials. Its efficiency is 1.42%.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.450.1-450.1
• /
• 2014

열에너지를 전기에너지로 변환하거나 또는 전기에너지를 열에너지로 직접 변환하는 열전 변환 기술이 주목받고 있다. 열전 변환 효율은 성능지수($ZT={\alpha}^2{\sigma}T{\kappa}^{-1}$)로 평가되며, 여기서 ${\alpha}$, ${\sigma}$, ${\kappa}$, T는 각각 열전재료의 제벡계수, 전기전도도, 열전도도 및 절대온도이다. 따라서 우수한 열전재료는 높은 제벡계수와 전기전도도 그리고 낮은 열전도도를 가져야 한다. Bismuth telluride는 상온영역에서 성능지수가 높은 재료로서, $Bi_2Te_3$에 $Bi_2Se_3$와 고용체를 형성하면 원자의 치환으로 포논산란에 의해 열전도도가 낮아지고, 도핑으로 전기적 특성을 조절하여 성능지수를 향상시킬 수 있다. 본 연구에서는 진공밀폐 용해법으로 $Bi_2Te_{2.85}Se_{0.15}:I_m$ (m=0.0~0.045) 고용체를 합성하여 상분석을 실시하고, 전자 이동특성 및 열전 특성을 평가하였다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.684-685
• /
• 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.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1996.06a
• /
• pp.516-518
• /
• 1996

Bimuth telluride type thermoelectrics are prepared by AC current applied got pressing method. It is possible to minimize the defects arising from the vaporization of Te, because of the very short processing time. The optimum conditions for the got pressing of 95mol% $Bi_2Te_3$-5mol%$Bi_2Se_3$ themoelectrics are sintered at $400^{\circ}C$, for 2min. with 1500 kgf/$cm^2$ from the particle size of 125 to 250 $\mu$m rang of powder. the resulted Z value (figure of merit) was 2.2$\times$10-3deg-1.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.05a
• /
• pp.41.1-41.1
• /
• 2007

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.209-209
• /
• 2005

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.34-34
• /
• 2005