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http://dx.doi.org/10.4313/JKEM.2011.24.4.340

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

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))
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.24, no.4, 2011 , pp. 340-344 More about this Journal
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.
Keywords
Metal organic chemical vapor deposition (MOCVD); Bismuth telluride ($Bi_2Te_3$); Substrate temperature; Growth mechanism; Thermoelectric;
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