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Thermoelectric Properties of Bi2Te3 Films Grown by Modified MOCVD with Substrate Temperatures

개조된 MOCVD법으로 성장한 Bi2Te3 박막의 기판온도에 따른 열전 특성

  • You, Hyun-Woo (Department of Electronic Materials Center materials research center, Korea Institute of Science and Technology(KIST)) ;
  • Kwon, O-Jong (Department of Materials Science and Engineering, Seoul National University) ;
  • Kim, Kwang-Chon (Department of Electronic Materials Center materials research center, Korea Institute of Science and Technology(KIST)) ;
  • Choi, Won-Chel (Department of Electronic Materials Center materials research center, Korea Institute of Science and Technology(KIST)) ;
  • Park, Chan (Department of Materials Science and Engineering, Seoul National University) ;
  • Kim, Jin-Sang (Department of Electronic Materials Center materials research center, Korea Institute of Science and Technology(KIST))
  • 유현우 (한국과학기술연구원 재료연구본부 전자재료센터) ;
  • 권오정 (서울대학교 재료공학부) ;
  • 김광천 (한국과학기술연구원 재료연구본부 전자재료센터) ;
  • 최원철 (한국과학기술연구원 재료연구본부 전자재료센터) ;
  • 박찬 (서울대학교 재료공학부) ;
  • 김진상 (한국과학기술연구원 재료연구본부 전자재료센터)
  • Received : 2010.02.08
  • Accepted : 2011.01.26
  • Published : 2011.04.01

Abstract

Thermoelectric bismuth telluride ($Bi_2Te_3$) films were deposited on $4^{\circ}$ off oriented (001) GaAs substrates using a modified metal organic chemical vapor deposition (MOCVD) system. The effects of substrate temperature on surface morphologies, crystallinity, electrical properties and thermoelctric properties were investigated. Two dimensional growth mode (2D) was observed at substrate temperature lower than $400^{\circ}C$. However, three dimensional growth mode (3D) was observed at substrate temperature higher than $400^{\circ}C$. Change of growth mechanism from 2D to 3D was confirmed with environmental scanning electron microscope (E-SEM) and X-ray diffraction analysis. Seebeck coefficients of all samples have negative values. This result indicates that $Bi_2Te_3$ films grown by modified MOCVD are n-type. The maximum value of Seebeck coefficient was -225 ${\mu}V/K$ and the power factor was $1.86{\times}10^{-3}\;W/mK^2$ at the substrate temperature of $400^{\circ}C$. $Bi_2Te_3$ films deposited using modified MOCVD can be used to fabricate high-performance thermoelectric devices.

Acknowledgement

Supported by : 나노기반 정보에너지 사업본부

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