Solid-State Synthesis of Te-Doped Mg₂Si

Authors: Jung, Jae-Yong¹; Kim, Il-Ho²

Source: Journal of Electronic Materials, Volume 40, Number 5, May 2011 , pp. 1144-1149(6)

Publisher: Springer

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Abstract:

Te-doped Mg₂Si (Mg₂Si:Te_m, m = 0, 0.01, 0.02, 0.03, 0.05) alloys were synthesized by a solid-state reaction and mechanical alloying. The electronic transport properties (Hall coefficient, carrier concentration, and mobility) and thermoelectric properties (Seebeck coefficient, electrical conductivity, thermal conductivity, and figure of merit) were examined. Mg₂Si was synthesized successfully by a solid-state reaction at 673 K for 6 h, and Te-doped Mg₂Si powders were obtained by mechanical alloying for 24 h. The alloys were fully consolidated by hot-pressing at 1073 K for 1 h. All the Mg₂Si:Te_m samples showed n-type conduction, indicating that the electrical conduction is due mainly to electrons. The electrical conductivity increased and the absolute value of the Seebeck coefficient decreased with increasing Te content, because Te doping increased the electron concentration considerably from 10¹⁶ cm⁻³ to 10¹⁸ cm⁻³. The thermal conductivity did not change significantly on Te doping, due to the much larger contribution of lattice thermal conductivity over the electronic thermal conductivity. Thermal conduction in Te-doped Mg₂Si was due primarily to lattice vibrations (phonons). The thermoelectric figure of merit of intrinsic Mg₂Si was improved by Te doping.

Keywords: Thermoelectric; Mg2Si; solid-state reaction; mechanical alloying; hot-pressing

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s11664-011-1558-4

Affiliations: 1: Department of Materials Science and Engineering, Chungju National University, Chungju, Korea 2: Department of Materials Science and Engineering, Chungju National University, Chungju, Korea, Email: ihkim@cjnu.ac.kr

Publication date: 2011-05-01