Solid-State Synthesis and Thermoelectric Properties of Al-Doped Mg2Si

• Published in: Journal of electronic materials 2012-06, Vol.41 (6), p.1675-1679
• Main Authors: You, Sin-Wook, Park, Kwan-Ho, Kim, Il-Ho, Choi, Soon-Mok, Seo, Won-Seon, Kim, Sun-Uk
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Electronic transport in condensed matter; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Materials; Materials Science; Optical and Electronic Materials; Physics; Solid State Physics; Thermoelectric and thermomagnetic effects
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-011-1786-7

The electronic transport and thermoelectric properties of Al-doped Mg 2 Si (Mg 2 Si:Al m , m  = 0, 0.005, 0.01, 0.02, 0.03) compounds prepared by solid-state synthesis were examined. Mg 2 Si was synthesized by solid-state reaction (SSR) at 773 K for 6 h, and Al-doped Mg 2 Si powders were obtained by mechanical alloying (MA) for 24 h. Mg 2 Si:Al m were fully consolidated by hot pressing (HP) at 1073 K for 1 h, and all samples showed n -type conduction, indicating that the electrical conduction is due mainly to electrons. The electrical conductivity increased significantly with increasing Al doping content, and the absolute value of the Seebeck coefficient decreased due to the significant increase in electron concentration from 10 16 cm −3 to 10 19 cm −3 by Al doping. The thermal conductivity was increased slightly by Al doping, but was not changed significantly by the Al doping content due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity. Mg 2 Si:Al 0.02 showed a maximum thermoelectric figure of merit of 0.47 at 823 K.