Si80Ge20B0.6 thermoelectric alloys with minute erbium (Er) addition were prepared by the spark plasma sintering technique. The samples with different amounts of Er additions were analyzed by x-ray diffraction, x-ray fluorescence, and x-ray photoelectron spectroscopy. The thermoelectric properties were measured from 400 to 900 K. Effects of the amount of Er addition on the thermoelectric properties of Si80Ge20B0.6 alloys were investigated. New findings indicate that the Er-added alloys have larger carrier concentrations than the pristine sample. The larger carrier concentration appears to make a significant contribution to the electrical conductivity. Seebeck coefficient decreases with the increase of carrier concentration, whereas the power factor increases with increasing electrical conductivity. It was generally believed that the scattering of phonons by carriers may result in the thermal conductivity reduction. The samples with Er addition exhibit better figure of merits than the pristine sample. The optimal ratio of Er addition is actually in the range of 0.085–0.125 at.%.
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G.A. Slack and M.A. Hussain: The maximum possible conversion efficiency of silicon-germanium thermoelectric generators. J. Appl. Phys. 70, 2694 (1991).
C.B. Vining: A model for the high-temperature transport properties of heavily doped n-type silicon-germanium alloys. J. Appl. Phys. 69, 331 (1991).
G.-Y. Xu, H.-W. Jiang, C.-Y. Zhang, X.-F. Wu, and S.-T. Niu: Thermoelectric properties on n-type Si80Ge20 with different dopants, in Int. Conf. Thermoelectr. Proc. (Piscataway, NJ, 2006), pp. 272–275.
J.P. Dismukes, L. Ekstrom, E.F. Steigmeier, I. Kudman, and D.S. Beers: Theory of deep impurities in silicon-germanium alloys. J. Appl. Phys. 35, 2899 (1964).
C.B. Vining, W. Laskow, J.O. Hanson, V.D. Beck, and P.D. Gorsuch: Thermoelectric properties of pressure-sintered Si0.8Ge0.2 thermoelectric alloys. J. Appl. Phys. 69, 4333 (1991).
Y.-D. Xu, G.-Y. Xu, and C.-C. Ge: The research trends of SiGe alloys thermoelectric materials. Mater. Rev. 21, 102 (2007).
Y.-D. Xu, G.-Y. Xu, and C.-C. Ge: Improvement in thermoelectric properties of n-type Si95Ge5 alloys by heavy multi-dopants. Scr. Mater. 58, 1070 (2008).
K. Fuda and S. Sugiyama: Effect of rare-earth cation doping on enhancement of the thermoelectric power of zinc oxide, Materials and Technologies for Direct Thermal-to-Electric Energy Conversion, edited by J. Yang, T.P. Hogan, R. Funahashi, and G.S. Nolas (Mater. Res. Soc. Symp. Proc. 886, Warrendale, PA, 2006), p. 473.
N.V. Nong, C.-J. Liu, and M. Ohtaki: High-temperature thermoelectric properties of late rare earth-doped Ca3Co4O9+δ. J. Alloy. Comp. 509, 977 (2011).
M. Ito, T. Nagira, and S. Hara: Thermoelectric properties of NaxCo2O4 with rare-earth metals doping prepared by polymerized complex method. J. Alloy. Comp. 408, 1217 (2006).
P. Ren, R.-G. Wu, Y.-H. Zhang, and G.-Y. Xu: Effects of Gd on thermoelectric properties of Bi2Te3 based materials. J. Mater. Sci. Eng. 28, 279 (2010).
G.-Y. Xu, S.-T. Niu, L.-L. Zhang, and C.-C. Ge: Thermoelectric properties of MyCoSb3 (M= Dy and Er) containing fullerite, in Int. Conf. Thermoelectr. ICT Proc. (Piscataway, NJ, 2003), pp. 52–55.
B.C. Sales: Electron crystals and phonon glasses: A new path to improved thermoelectric materials. MRS Bull. 23, 15 (1998).
D.M. Rowe: CRC Handbook of Thermoelectrics (CRC Press, Boca Raton, FL, 1995), p. 211.
B. Abeies, D.S. Beers, G.D. Cody, and J.P. Dismukes: Thermal conductivity of Ge-Si alloys at temperature. Phys. Rev. 125, 44 (1962).
G. Min and D.M. Rowe: High-temperature heat treatment of silicon germanium gallium phosphide alloys. J. Appl. Phys. 70, 3843 (1991).
N. Scoville and J. Rolfe: Thermal conductivity reduction in SiGe alloys by the addition of nanophase particles. Nanostruct. Mater. 5, 20 (1995).
S.L. Draper, J.W. Vandersande, C. Wood, R. Masters, and V. Raag: Effect of Ga and P dopants on the thermoelectric properties of n-type SiGe, in Proc. Intersoc. Energy Convers. Eng. Conf. (Washington, DC, 1989), pp. 711–714.
N. Scoville, C. Bajgar, J. Rolfe, J.P. Fleurial, and J. Vandersande: Optimization of hot-pressed n-type and p-type SiGe thermoelectric materials, in Proc. Intersoc. Energy Convers. Conf. 1 (Atlanta, GA, 1993), pp. 227–233.
J.P. Fleurial, T. Caillat, and A. Borshchevsky: Skutterudites, a new class of promising thermoelectric materials, in AIP Conf. Proc. (Kansas, MO, 1995), pp. 40–44.
G. Joshi, H. Lee, and Y.-C. Lan: Enhanced thermoelectric figure-of-merit in nanostructured p-type silicon germanium bulk alloys. Nano Lett. 8, 4670 (2008).
J.F. Gibbons, J.L. Moll, and N.I. Meyer: The doping of semiconductors by ion bombardment. Nucl. Instrum. Methods 38, 165 (1965).
N. Sclar: Survey of dopants in silicon for 2-2.7 and 3-5 μm infrared detector application. Infrared Phys. 17, 71 (1977).
J. Jiang, L.-D. Chen, S.-Q. Bai, and Q. Yao: Thermoelectric performance of p-type Bi-Sb-Te materials prepared by spark plasma sintering. J. Alloy. Comp. 390, 208 (2005).
Y.-K. Chen, C. Chen, and L. Xiang: Effect on the properties of different preparation processes in Ca3Co4O9 thermoelectric material, in Int. Conf. Electr. Control Eng. Proc. (Wuhan, 2010), pp. 4672–4676.
J. Jiang, L.-D. Chen, S.-Q. Bai, Q. Yao, and Q. Wang: Fabrication and thermoelectric performance of textured n-type Bi2(Te, Se)3 by spark plasma sintering. Mater. Sci. Eng., B 117, 334 (2005).
Y.-D. Xu, G.-Y. Xu, Y.-H. Liu, and C.-C. Ge: Enhancement in thermoelectrical power factor of n-type Si80Ge20 alloys. J. Chin. Phys. Lett. 25, 2664 (2008).
C. Bajgar, R. Masters, N. Scoville, and J. Vandersande: Thermoelectric properties of hot pressed p-type SiGe alloys, in AIP Conf. Proc. 217 (Albuquerque, NM, 1991), pp. 440–445.
S.P. Luzan, V.E. Listovnichii, Y.I. Buyanov, and P.S. Martsenyuk: Phase diagram of the binary erbium-silicon system and physical properties of erbium silicides up to 1050 °C. J. Alloy. Comp. 239, 77 (1996).
J.-M. Li, H.-L. Tu, A.-S. Zheng, Z.-J. Deng, and Z.-Q. Luo: Growth of (100) Zn-doped GaSb single crystals. Chinese J. Rare Metals 25, 321 (2001).
R.A. Hutner and E.S. Rittner: Fermi levels in semiconductors. Philips Res. Rep. 5, 188 (1950).
C.M. Bhandari and D.M. Rowe: Silicon-germanium alloys as high-temperature thermoelectric materials. J. Contem. Phys. 21, 219 (1980).
D.M. Rowe and S.G.K. Williams: Comments on the thermoelectric properties of pressure-sintered Si0.8Ge0.2 thermoelectric alloys. J. Appl. Phys. 73, 4683 (1993).
G.-A. Slack: Thermal conductivity of pure and impure silicon, silicon carbide, and diamond. J. Appl. Phys. 35, 3460 (1964).
H.R. Meddins and J.E. Parrott: The thermal and thermoelectric properties of sintered germanium-silicon alloys. J. Phys. C: Solid State Phys. 9, 1263 (1976).
The authors acknowledge the financial support of this work from the Scientific Research Startup Fund Project of Beijing Municipal Bureau of Personnel (Q2009012200801).
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Zhao, R., Shen, L. & Guo, F. Enhanced electrical conductivity in Si80Ge20B0.6 alloys with Er addition prepared by spark plasma sintering. Journal of Materials Research 26, 1879–1885 (2011). https://doi.org/10.1557/jmr.2011.127