Enhanced thermoelectric figure of merit in nanostructured n-type silicon germanium bulk alloy

The dimensionless thermoelectric figure of merit (ZT) of the n-type silicon germanium (SiGe) bulk alloy at high temperature has remained at about one for a few decades. Here we report that by using a nanostructure approach, a peak ZT of about 1.3 at 900 °C in an n-type nanostructured SiGe bulk alloy has been achieved. The enhancement of ZT comes mainly from a significant reduction in the thermal conductivity caused by the enhanced phonon scattering off the increased density of nanograin boundaries. The enhanced ZT will make such materials attractive in many applications such as solar, thermal, and waste heat conversion into electricity.

[1]  Gang Chen,et al.  Thermal conductivity modeling of periodic two-dimensional nanocomposites , 2004 .

[2]  Cronin B. Vining,et al.  A model for the high‐temperature transport properties of heavily doped n‐type silicon‐germanium alloys , 1991 .

[3]  Cronin B. Vining,et al.  Thermoelectric properties of pressure-sintered Si0.8Ge0.2 thermoelectric alloys , 1991 .

[4]  William A. Goddard,et al.  Silicon nanowires as efficient thermoelectric materials , 2008, Nature.

[5]  G. Chen,et al.  Chapter 5 - Phonon Transport in Low-Dimensional Structures , 2001 .

[6]  M. Dresselhaus,et al.  New Directions for Low‐Dimensional Thermoelectric Materials , 2007 .

[7]  Gang Chen,et al.  Enhanced thermoelectric figure-of-merit in p-type nanostructured bismuth antimony tellurium alloys made from elemental chunks. , 2008, Nano letters.

[8]  A. Majumdar,et al.  Enhanced thermoelectric performance of rough silicon nanowires , 2008, Nature.

[9]  Mildred S. Dresselhaus,et al.  Effect of quantum-well structures on the thermoelectric figure of merit. , 1993, Physical review. B, Condensed matter.

[10]  Gang Chen,et al.  Thermal conductivity and ballistic-phonon transport in the cross-plane direction of superlattices , 1998 .

[11]  C Wood,et al.  Materials for thermoelectric energy conversion , 1988 .

[12]  Rama Venkatasubramanian,et al.  Thermal conductivity of Si–Ge superlattices , 1997 .

[13]  D. Rowe,et al.  Comments on the thermoelectric properties of pressure‐sintered Si0.8Ge0.2 thermoelectric alloys , 1993 .

[14]  M. Dresselhaus,et al.  High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys , 2008, Science.

[15]  D. Rowe.  CRC Handbook of Thermoelectrics , 1995 .

[16]  Moayyed A. Hussain,et al.  The maximum possible conversion efficiency of silicon‐germanium thermoelectric generators , 1991 .

[17]  D. Rowe,et al.  Silicon–germanium alloys as high-temperature thermoelectric materials , 1980 .

[18]  Kang L. Wang,et al.  Measurements of anisotropic thermoelectric properties in superlattices , 2002 .

[19]  A. Majumdar,et al.  Characterization of heat transfer along a silicon nanowire using thermoreflectance technique , 2006, IEEE Transactions on Nanotechnology.

[20]  R. Venkatasubramanian,et al.  Thin-film thermoelectric devices with high room-temperature figures of merit , 2001, Nature.

[21]  M. P. Walsh,et al.  Quantum Dot Superlattice Thermoelectric Materials and Devices , 2002, Science.