0.2wt% SbI3 첨가 90% Bi2Te3-(10-x)% Sb2Te3-x% Sb2Se3 고용체 합금의 전기적특성 및 열전특성

현도빈,황종승,심재동,오태성,Barabash, V . A . 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.8

Electrical and thermoelectric properties of the 0.2 wt% SbI₃- doped n-type 90% Bi₂Te₃-(10-x)% Sb₂Te₃-x% Sb₂Se₃ single crystals have been investigated at temperatures ranging from 77K to 600K. The carrier concentration and Seebeck coefficient were independent of the Sb₂Se₃ content. With increasing the Sb₂Se₃ content, the electrical resistivity increased and Hall mobility decreased, which was attributed to the lattice distortion. The thermal conductivity decreased with increasing Sb₂Se₃ content, which was mainly due to the decrease of the electronic thermal conductivity. With increasing the Sb₂Se₃ content, the maximum figure-of-merit decreased and was shifted to the lower temperature. The 0.2 wt% SbI₃-doped 90% Bi₂Te₃-5% Sb₂Te₃-5% Sb₂Se₃ single crystal showed the maximum figure-of-merit of 1.65×10^(-3)/K at 280K.

Zone melting 법으로 성장시킨 90 % Bi2Te3-10 % Bi2Se3 n 형 단결정에서 길이방향에 따른 열전특성의 변화

현도빈,하헌필 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.3

CdI₂ and CdCl₂ doped n-type 90% Bi₂Te₃ 10% Bi₂Se₃ single crystals were grown by the vertical zone melting method, and the thermoelectric properties along the ingot were analyzed. The sharp increase of the Seebeck coefficient and electrical resistivity at the last-to-freeze region were considered as a result of the evaporation of I and Cl from the molten zone. The maximum Figure-of-Merit of the CdI₂ and CdCl₂ doped n-type 90% Bi₂Te₃ 10% Bi₂Se₃ single crystals were 2.7×10^(-3)/K and 2.8×10^(-3)/K, respectively. The higher Figure-of-Merit for the CdCl₂ doped specimens was mainly due to the lower (κ-κ_(el)). The optimum doping amount of CdI₂ and CdCl₂ for n-type 90% Bi₂Te₃-10% Bi₂Se₃ single crystals, grown by the vertical zone melting method, were 0.075-0.10 wt% and 0.04-0.05 wt%, respectively.

Sbi3 를 첨가한 25% Bi2Te3-75% Sb2Te3 와 15% Bi2Te3-85% Sb2Te3 단결정의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.8

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 15% Bi₂Te₃-85% Sb₂Te₃ single crystals, grown by the Bridgman method, were measured at temperatures ranging from 77 K to 600 K. For the Sb₂Te₃-rich single crystals, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents and added amount of SbI₃. The temperature dependences of (m*/m_o)^(3/2)·μ_c and effective mass m*/m_o were T^(-1.5) and T^(-1/3), respectively. The decrease of the saturated hole concentration and the change of the slope of the Seebeck coefficient with temperature were considered in the view point of the two sub-bands in the valence band. The maximum figure-of-merit at 300 K of 0.2 wt% SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 0.4 wt% SbI₃-doped 15% Bi₂Te₃-85% Sb₂Te₃ single crystals were 2.25×10^(-3)/K and 1.95×10^(-3)/K, respectively.

기계적 합금화 공정으로 제조한 p형 (Bi0.25 Sb0.75)2 Te3 의 열전특성

현도빈,심재동,정부양,오태성,남등의 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.1

Formation of (Bi_(0. 25)Sb_(0. 75))₂Te₃ alloy was completed by mechanical alloying of the as-mixed Bi, Sb, and Te granules of ∼5 ㎜ size for 5 hours at ball-to-material ration of 5:1. When hot pressed at temperatures ranged from 300℃ to 550℃ for 30 minutes, figure of merit of (Bi_(0. 25)Sb_(0. 75))₂Te₃ increased with increasing hot pressing temperature and maximum value of 2.8×10^(-3)/K could be obtained by hot pressing at 550℃. When hot pressed at 400℃, figure of merit was increased from 2.0×10^(-3)/K to 2.37×10^(-3)/K with addition of 1.25 wt% Sb as an acceptor dopant. With further addition of Sb, however, figure of merit was abruptly decreased. When hot pressed at 550℃, figure of merit(∼2.8×10^(-3)/K) was little changed with addition of Sb up to 2 wt%, and then decreased abruptly below 0.5×10^(-3)/K with further addition of Sb.

SbI3 를 첨가한 33.3 % Bi2Te3-66.7 % Sb2Te3 열전반도체의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,황창원 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.2

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 33.3% Bi₂Te₃66.7% Sb₂Te₃ single crystals have been measured at temperatures ranging from 77K to 600K. The scattering parameter of the 33.3 Bi₂Te₃-66.7% Sb₂Te₃ single crystals was determined as s = 0. With increasing the amount of SbI₃ dopant, the hole concentration of the 33.3% Bi₂Te₃-66,7% Sb₂Te₃ single crystal is decreased, resulting in the increment of the Seebeck coefficient and electrical resistivity, and the temperature for the maximum figure-of-merit shifted to lower temperature. A maximum figure-of-merit of 2.3×10^(-3)/K was obtained for 0.3 wt% SbI₃-doped specimen. It has been revealed that. the addition of SbI₃ as a donor dopant is useful in controlling the hole concentration of p-type 33.3% Bi₂Te₃ 66.7% Sb₂Te₃ alloy system.

BN 을 산란센터로 첨가한 (Bi0.2Sb0.8)2Te3 가압소결체의 열전특성

현도빈,오태성,이준수,김항종 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.9

Thermoelectric properties of the polycrystalline (Bi_(0.2)Sb_(0.8))₂Te₃, fabricated by mechanical alloying and hot-pressing, were investigated with addition of BN as scattering centers. The Seebeck coefficient of the hot-pressed (Bi_(0.2)Sb_(0.8))₂Te₃ was not affected by addition of BN. The thermal conductivity of the hot-pressed (Bi_(0.2)Sb_(0.8))₂Te₃ decreased with increasing the volume fraction of BN due to the reduction of k_(el) However, the lattice thermal conductivity k_(ph) was little varied with addition of BN. The figure-of-merit of the hot-pressed (Bi_(0.2)Sb_(0.8))₂Te₃ was 3.05×10^(-3)/K without addition of BN and was lowered with increasing the volume fraction of BN, because the increase of the electrical resistivity was larger than the reduction of the thermal conductivity due to the grain refinement.

$\textrm{SbI}_{3}$를 첨가한 85% $\textrm{Bi}_{2}\textrm{Te}_{3}$-15% $\textrm{Bi}_{2}\textrm{Se}_{3}$ 열반도체의 전기적 특성과 열전 특성

현도빈,황종승,오태성,유병철,황창원,Hyeon, Do-Bin,Hwang, Jong-Seung,O, Tae-Seong,Yu, Byeong-Cheol,Hwang, Chang-Won 한국재료학회 1998 한국재료학회지 Vol.8 No.5

Electrical and Thermoelectric Properties of$ SbI_{3}$-doped 85% 85% $BiTe_{2}$$Se_{3}$ 단결정에서 전하 이동에 대한 살란인자는 0.1이었으며, 전자이동도와 정공이동도의 비($\mu_{e}$ /$\mu_{h}$ )는 1.45이었다. $SbI_{3}$의 첨가량이 증가할수록 전자 농도의 증가로 Seebek 계수와 전기비저항이 감소하며, Seebeck 계수와 전기비저항이 최대값을 나타내는 온도가 고온으로 이동하였다. $SbI_{3}$를 첨가한 85%$Bi_{2}$$Te_{3}$단결정에서 성능지수의 최대값은 $SbI_{3}$를 0.1 wt%첨가한 조성에서 $2.0 x 10^{-3}$ K이었다.

(100-x)%Bi2Te3-x%Sb2Te3(x≥66.7) 단결정의 전기적 특성과 열전특성

현도빈,심재동,오태성,하헌필,한동균 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.11

Electrical and thermoelectric properties of the undoped (100-x)% Bi₂Te₃-x% Sb₂Te₃ (x≥66.7) pseudo-binary single crystals grown by the zone melting method were measured over the temperature range from 77 to 600K. For the (100-x)% Bi₂Te₃-x% Sb₂Te₃ (x≥66.7) alloys, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents. The temperature dependences of (m^*/m_o)^(3/2)·μ_c and the effective mass were proportional to T^(-1.5) and T^(-1/3), respectively. The saturated hole concentration decreased with increasing temperature and the slope of the Seebeck coefficient changed at about 350K, which implied the two sub-bands in the valence band. While the 33.3% Bi₂Te₃-66.7% Sb₂Te₃ alloy exhibited the highest figure-of-merit among the undoped Bi₂Te₃-Sb₂Te₃ alloys, the maximum figure-of-merit could be expected fur the 22.5% Bi₂Te₃-77.5% Sb₂Te₃ alloy with optimizing the carrier concentration.

Al 탈산강의 (脫酸鋼) Ca 첨가에 의한 비금속개재물의 (非金屬介在物) 형태제어

현도빈,심재동,이원재,윤종규 대한금속재료학회 1982 대한금속재료학회 학술대회 개요집 Vol.1982 No.1

Zone melting furnace 온도와 성장속도가 90 % Bi2Se3n 형 단결정의 열전특성에 미치는 영향

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.1

The effects of the zone melting temperature and growth rate on the thermoelectric properties for 0.15 wt% CdI₂ and 0.05 wt% CdCl₂ doped 90% Bi₂Te₃-10% Bi₂Se₃ single crystals were investigated. The Seebeck coefficient and electrical resistivity of the 0.15 wt% CdI₂ doped single crystals were initially decreased along the ingots due to the condensation of iodine in the melts. The sharp increase of the Seebeck coefficient and electrical resistivity at the last-to-freeze region were considered as results of the evaporation of iodine from the molten zone and the compensation of electrons due to the formation of the antistructure defects. The figure-of-merit was enhanced with increasing the zone melting temperature and lowering the growth rate. The single crystels grown at the zone melting temperature of 800℃ and the growth rate of 0.1 ㎜/min exhibited the maximum figure-of-merit of 2.8×10^(-3)/K.