SiGe alloys belong to the class of classic high temperature thermoelectric materials. By the means of nanostructuring, the performance of this well-known material can be further enhanced. Additional grain boundaries and point defects added to the alloy structure result in a strong decrease in thermal conductivity because of reduced lattice contribution to the overall thermal conductivity. Hence, the figure of merit can be increased. To obtain a nanostructured bulk material, a nanosized raw material is essential. In this work, a new approach toward nanostructured SiGe alloys is presented where alloyed nanoparticles are synthesized from a homogeneous mixture of the respective precursors in a microwave plasma reactor. As-prepared nanoparticles are compacted to a dense bulk material by a field assisted sintering technique. A figure of merit of zT = 0.5 ± 0.09 at 450 °C and a peak zT of 0.8 ± 0.15 at 1000 °C could be achieved for a nanostructured, 0.8% phosphorus-doped Si80Ge20 alloy without any further optimization.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
A. Majumdar: Thermoelectricity in semiconductor nanostructures. Science 303, 777 (2004).
B. Poudel, Q. Hao, Y. Ma, Y. Lan, A. Minnich, B. Yu, X. Yan, D. Wang, A. Muto, D. Vashaee, X. Chen, J. Liu, M.S. Dresselhaus, G. Chen, and Z. Ren: High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys. Science 320, 634 (2008).
Y. Lan, A.J. Minnich, G. Chen, and Z. Ren: Enhancement of thermoelectric figure-of-merit by a bulk nanostructuring approach. Adv. Funct. Mater. 20, 357 (2010).
X. Yan, G. Joshi, W. Liu, Y. Lan, H. Wang, S. Lee, J.W. Simonson, S.J. Poon, T.M. Tritt, G. Chen, and Z.F. Ren: Enhanced thermoelectric figure of merit of p-type half-Heuslers. Nano Lett. 11, 556 (2011).
S.K. Bux, R.G. Blair, P.K. Gogna, H. Lee, G. Chen, M.S. Dresselhaus, R.B. Kaner, and J.-P. Fleurial: Nanostructured bulk silicon as an effective thermoelectric material. Adv. Mater. (19, 2445 (2009).
A.I. Boukai, Y. Bunimovich, J. Tahir-Kheli, J.-K. Yu, W.A. Goddard Iii, and J.R. Heath: Silicon nanowires as efficient thermoelectric materials. Nature 451, 168 (2008).
N. Mingo, D. Hauser, N.P. Kobayashi, M. Plissonnier, and A. Shakouri: “Nanoparticle-in-Alloy” approach to efficient thermoelectrics: silicides in SiGe. Nano Lett. 9, 711 (2009).
X.W. Wang, H. Lee, Y.C. Lan, G.H. Zhu, G. Joshi, D.Z. Wang, J. Yang, A.J. Muto, M.Y. Tang, J. Klatsky, S. Song, M.S. Dresselhaus, G. Chen, and Z.F. Ren: Enhanced thermoelectric figure of merit in nanostructured n-type silicon germanium bulk alloy. Appl. Phys. Lett. 93, 193121 (2008).
G.H. Zhu, H. Lee, Y.C. Lan, X.W. Wang, G. Joshi, D.Z. Wang, J. Yang, D. Vashaee, H. Guilbert, A. Pillitteri, M.S. Dresselhaus, G. Chen, and Z.F. Ren: Increased phonon scattering by nanograins and point defects in nanostructured silicon with a low concentration of germanium. Phys. Rev. Lett. 102, 196803 (2009).
A. Gurav, T. Kodas, T. Pluym, and Y. Xiong: Aerosol processing of materials. Aerosol Sci. Technol. 19, 411 (1993).
J. Knipping, H. Wiggers, B. Rellinghaus, P. Roth, D. Konjhodzic, and C. Meier: Synthesis of high purity silicon nanoparticles in a low pressure microwave reactor. J. Nanosci. Nanotechnol. 4, 1039 (2004).
Z. Munir, U. Anselmi-Tamburini, and M. Ohyanagi: The effect of electric field and pressure on the synthesis and consolidation of materials: A review of the spark plasma sintering method. J. Mater. Sci. 41, 763 (2006).
G. Schierning, R. Theissmann, H. Wiggers, D. Sudfeld, A. Ebbers, D. Franke, V.T. Witusiewicz, and M. Apel: Microcrystalline silicon formation by silicon nanoparticles. J. Appl. Phys. 103, 084305 (2008).
J.P. Dismukes, L. Ekstrom, and R.J. Paff: Lattice parameter and density in germanium-silicon alloys. J. Phys. Chem. 68, 3021 (1964).
J. Rodriguez-Carvajal: FULLPROF: A program for Rietveld refinement and pattern matching analysis. Abstracts of the Satellite Meeting on Powder Diffraction of the XV Congress of the IUCr, Toulouse, France, 1990, p. 127.
J.A. Cape and G.W. Lehman: Temperature and finite pulse-time effects in the flash method for measuring thermal diffusivity. J. Appl. Phys. 34, 1909 (1963).
D. Schwesig, G. Schierning, R. Theissmann, N. Stein, N. Petermann, H. Wiggers, R. Schmechel, and D.E. Wolf: From nanoparticles to nanocrystalline bulk: Field assisted sintering of silicon nanoparticles. Nanotechnology 22, 135601 (2011).
M.M. Rieger and P. Vogl: Electronic-band parameters in strained Si1-xGex alloys on Si1-yGey substrates. Phys. Rev. B 48, 14276 (1993).
F. Schäffler: SiGe, in Properties of Advanced Semiconductor Materials GaN, AlN, InN, BN, SiC, SiGe, edited by M.E. Levinshtein, S.L. Rumyantsev, and M.S. Shur (John Wiley & Sons, New York, 2001), pp. 149–188.
A.R. Stegner, R.N. Pereira, R. Lechner, K. Klein, H. Wiggers, M. Stutzmann, and M.S. Brandt: Doping efficiency in freestanding silicon nanocrystals from the gas phase: Phosphorus incorporation and defect-induced compensation. Phys. Rev. B 80, 165326 (2009).
H. Lee, D. Wang, W. Wang, Z. Ren, B. Klotz, M.Y. Tang, R. Yang, P. Gogna, J-P. Fleurial, M.S. Dresselhaus, and G. Chen: Thermoelectric properties of Si/Ge nano-composite. International Conference on Thermoelectrics, ICT Proceedings, June 19–23, 2005, pp. 269–271.
H.R. Meddins and J.E. Parrot: The thermal and thermoelectric properties of sintered germanium-silicon alloys. J. Phys. C: Solid State Phys. 9, 1263 (1976).
D.M. Rowe, V.S. Shukla, and N. Savvides: Phonon scattering at grain boundaries in heavily doped fine-grained silicon-germanium alloys. Nature 290, 765 (1981).
D.M. Rowe and V.S. Shukla: The effect of phonon-grain boundary scattering on the lattice thermal conductivity and thermoelectric conversion efficiency of heavily doped fine-grained, hot-pressed silicon germanium alloy. J. Appl. Phys. 52, 7421 (1981).
M. Takashiri, T. Borca-Tasciuc, A. Jacquot, K. Miyazaki, and G. Chen: Structure and thermoelectric properties of boron doped nanocrystalline Si0.8Ge0.2 thin film. J. Appl. Phys. 100, 054315 (2006).
We thank M. Winterer and D. Gautam, Faculty of Engineering, for the use of the spark plasma sintering machine and M. Farle, Department of Experimental Physics, for the possibility to use the microscopy facilities. Financial supports from the German Research Foundation (Deutsche Forschungsgemeinschaft) within the priority program SPP 1386: Nanostrukturierte Thermoelektrika, the European Union and the Ministry of Economic Affairs and Energy of the State North Rhine–Westphalia in Germany within the frame of an Objective 2 Programme (European Regional Development Fund) are gratefully acknowledged.
About this article
Cite this article
Stein, N., Petermann, N., Theissmann, R. et al. Artificially nanostructured n-type SiGe bulk thermoelectrics through plasma enhanced growth of alloy nanoparticles from the gas phase. Journal of Materials Research 26, 1872–1878 (2011). https://doi.org/10.1557/jmr.2011.117