Enhanced figure of merit of a porous thin film of bismuth antimony telluride

A porous thin film of Bi0.4Te3Sb1.6 with an enhanced figure of merit of 1.8 at room temperature was fabricated by flash evaporation on an alumina substrate containing hexagonally arranged nanopores with an average diameter of 20 nm, separated by an average distance of 50 nm. The thermal conductivity was significantly reduced compared with standard Bi0.4Te3Sb1.6 films to 0.25 W/(m⋅K) with no major decrease in either the electrical conductivity (398 S/cm) or the Seebeck coefficient (198 μV/K). The reduction in thermal conductivity was rationalized using a model for the full distribution of the phonon mean free path in the film.

[1]  D. Thouless.  Percolation Theory and Electrical Conductivity , 1971 .

[2]  Il-ho Kim.  Electronic transport properties of the flash-evaporated p-type Bi0.5Sb1.5Te3 thermoelectric thin films , 2000 .

[3]  M. Takashiri,et al.  Preparation and characterization of Bi0.4Te3.0Sb1.6 nanoparticles and their thin films , 2008 .

[4]  Hideki Masuda,et al.  Fabrication of gold nanodot array using anodic porous alumina as an evaporation mask , 1996 .

[5]  Hiroshi Tsukamoto,et al.  Structural and thermoelectric properties of fine-grained Bi0.4Te3.0Sb1.6 thin films with preferred orientation deposited by flash evaporation method , 2008 .

[6]  Watson,et al.  Lower limit to the thermal conductivity of disordered crystals. , 1992, Physical review. B, Condensed matter.

[7]  C. L. Tien,et al.  Thermal diffusivity measurement of GaAs/AlGaAs thin-film structures , 1994 .

[8]  Akira Ono,et al.  Electrical delay technique in the picosecond thermoreflectance method for thermophysical property measurements of thin films , 2005 .

[9]  A. Majumdar,et al.  Nanoscale thermal transport , 2003, Journal of Applied Physics.

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

[11]  Baoling Huang,et al.  Ab initio and molecular dynamics predictions for electron and phonon transport in bismuth telluride , 2008 .

[12]  E. Schaub,et al.  Homodyne detection technique using spontaneously generated reference signal in picosecond thermoreflectance measurements , 2003 .

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

[14]  M. Takashiri,et al.  Fabrication and characterization of Bi0.4Te3.0Sb1.6 thin films by flash evaporation method , 2007 .

[15]  Thermal conductivity of nanoporous bismuth thin films , 2004 .

[16]  J. Tominaga,et al.  Thermal conductivity of low-k films of varying porosity and direct measurements on silicon substrate , 2009 .

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

[18]  E. A. Miller,et al.  Preparation, Phase‐Boundary Energies, and Thermoelectric Properties of InSb‐Sb Eutectic Alloys with Ordered Microstructures , 1963 .

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

[20]  Ali Shakouri,et al.  Heat Transfer in Nanostructures for Solid-State Energy Conversion , 2002 .

[21]  S. Shtrikman,et al.  A Variational Approach to the Theory of the Effective Magnetic Permeability of Multiphase Materials , 1962 .

[22]  Gang Chen,et al.  Theoretical phonon thermal conductivity of Si/Ge superlattice nanowires , 2004 .

[23]  G. J. Snyder,et al.  Complex thermoelectric materials. , 2008, Nature materials.

[24]  J. Callaway.  Model for Lattice Thermal Conductivity at Low Temperatures , 1959 .