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Detailed Program
Paper Number : TE-O02
Time Frame : 11:47~11:59
Presentation Date : Thurse day, 27, November
Session Name : Thermoelectrics
Session Chair 1# : Soonil Lee
Session Chair 2# : Yoshiaki Kinemuchi
Thermoelectric Properties of Bulk Bi2Mg2/3Nb4/3O7-Bi (BMNO-Bi) Composite and BMNO-Bi Composite Thin Films
Ji-Ho EOM
Chungnam National University
Thermoelectric materials have the unique capability to directly convert heat to electricity and provide spot cooling or heating. Thermoelectric devices for energy conversion and temperature control have widely exploited in many industrials field. The primary candidate technology for miniaturizing thermoelectric devices is to apply semiconductor-processing technologies including thin film process. A practical thermoelectric material should have high Seebeck coefficient, high electrical conductivity, and low thermal conductivity.
Bismuth magnesium niobium oxide (Bi2Mg2/3Nb4/3O7) has low thermal conductivity owing to its pyrochlore structure [1]. Especially, BMNO is easily reduced in the reduced atmosphere, resulting in a self - assembled Bi metal into the BMNO films grown by pulsed laser deposition (PLD) in N2 atmosphere [2]. Therefore, electric property of BMNO was changed insulator to semiconductor. In the present study, self - assembled Bi metal into the BMNO thin films was compared with bulk type self - assembled Bi metal into the BMNO.
BMNO – Bi composite films were deposited on SiO2 / Si substrate by pulsed laser deposition with various thicknesses (100, 300, 500, 700, and 1000 nm). The BMNO–Bi thin films were measured for thermoelectric properties using TFTEP – 800 (SEEPEL Co. in Korea) at various temperatures (30 ~ 500 oC, 10 points). The BMNO – Bi thin films were measured thermal conductivity at room temperature (measured in Chung – Ang University). Bulk type BMNO specimen was sintered using furnace at air atmosphere. BMNO – Bi specimen was annealed at Ar atmosphere. Bulk type BMNO – Bi specimen was measured thermoelectric properties using ZEM – 2 : M8/L (ULVAC Co. in Japan) at various temperatures (30 ~ 500 oC, 10 points). The thermal conductivity of the bulk type BMNO – Bi specimen was measured at room temperature.
Through this study, BMNO can be applied for the thermoelectric property. This study will contribute to find new thermoelectric materials using insulators.

References:

[1] David P. Cann, Clive A. Randall and Thomas R. Shrout, Solid State Communications, Vol. 100, No. 7, pp 529, 1996
[2] J.K Ahn, N.D Cuong, N.J Seong, and S.G Yoon, Journal of The Electrochemical Society, 156 (9) G134-G137 (2009)
Acknowledgements :