Challenges and Opportunities in Thermoelectric Energy ... and Opportunities in Thermoelectric Energy...

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  • Arun Majumdar, UC Berkeley

    Challenges and Opportunities in Thermoelectric Energy Conversion

    Arun Majumdar

    Department of Mechanical EngineeringUniversity of California, Berkeley

    Materials Sciences DivisionLawrence Berkeley Lab

    DOE, NSF, ONR, NASA

  • Arun Majumdar, UC Berkeley

    Thermoelectricity and Energy Conversion

    ab

    V

    T1 T2

    aSeebeck Coefficient, S = V/T

    Peltier Coefficient, = Q/I=ST

    pnpn

    R

    Qin

    Qout

    QinTcold

    Thotpnpn

    QoutI

    V

  • Arun Majumdar, UC Berkeley

    Thermoelectric Figure of Merit

  • Arun Majumdar, UC Berkeley

  • Arun Majumdar, UC Berkeley

  • Arun Majumdar, UC Berkeley

    Courtesy: Gang Chen

  • Arun Majumdar, UC Berkeley

    Origins of Thermoelectricity

  • Arun Majumdar, UC Berkeley

    Effect of Nanostructuring on S2

    (Dresselhaus et al., 1993)

  • Arun Majumdar, UC Berkeley

    Majumdar, Science 303, 777 (2004)

    PbSeTe/PbTe QD Superlattices

    Harman et al., Science 297, 2229 (2002)

    AgPb18SbTe20ZT = 2 @ 800K

    AgSb rich

    Hsu et al., Science 303, 818 (2004)

    kTSZT

    2

    =

    Venkatasubramanian et al. Nature 413, 597 (2001)

    Bi2Te3/Sb2Te3 Superlattices2.5-25nm

    kbulk = 0.49 W/m-Kkns = 0.22 W/m-K

  • Arun Majumdar, UC Berkeley

    k [W

    /m-K

    ]

    A B

    Alloy Limit

    Alloy limit of thermal conductivity in crystalline materials!

  • Arun Majumdar, UC Berkeley

    Li et al., Appl Phys Lett 83, 3186 (2003)Deyu Li, Yiying Wu, Rong Fan, Peidong Yang

    Nanowire

    Si/SiGe superlattice nanowires

  • Arun Majumdar, UC Berkeley

    ErAs Nanostructures Embedded in InGaAs

  • Arun Majumdar, UC Berkeley

    InGaAs

    ErAs/InGaAs

    Woochul Kim, Pramod Reddy, Josh Zide, Art Gossard

    Below Alloy Limit!

  • Arun Majumdar, UC Berkeley

    k =

    d

    dTeb ( )Planck BB1 2 3 v ( )

    Speed{ l ( )

    MeanFreePath{ d

    0

    max

    Frequency, max

    eb

    v

    Atoms/Alloys

    Nanostructures

    Phonon Scattering

    Hypothesis

  • Arun Majumdar, UC Berkeley

    Courtesy: Ed Croke, Hughes Res. Lab. for materials

    Si-Ge Superlattices

  • Arun Majumdar, UC Berkeley

    Cathode

    Barrier

    Anode

    Metallic contact for

    top connection

    100 microns

    Courtesy: John Bowers (UCSB); Ali Shakouri (UCSC)

    SEM Picture of Thin Film Coolers

  • Arun Majumdar, UC Berkeley

    X. Fan, G. Zeng, C. LaBounty, E.Croke, C. Ahn, J.E. Bowers, A. Shakouri, SiGeC/Si superlattice micro cooler, Applied Physics Lett., Vol. 78, No.11, 12

    March 2001.Featured in Nature Science Update, Physics Today, AIP April 2001

    n-Si/SiGeC Superlattice Micro Cooler

  • Arun Majumdar, UC Berkeley

    G. Zeng, X. Fan, C. LaBounty, J.E. Bowers, E.Croke, J. Christofferson, D. Vashaee, A. Shakouri, Direct Measurement of Cooling Power Density for Thin Film Suplerlattice Micro Coolers, submitted to APL 2002.

    Micro Refrigerator Integrated with Thin-Film Heater

  • Arun Majumdar, UC Berkeley

    Localized control of temperature on the chip.

    InP-based Micro Refrigerator & Micro Heater

  • Arun Majumdar, UC Berkeley

    Nanowire Array Composites and Devices

    2 m

    200 nm

    Majumdar Lab, UC Berkeley

  • Arun Majumdar, UC Berkeley

    Majumdar, Science 303, 777 (2004)

    Challenges and Opportunities in Thermoelectric Energy ConversionThermoelectricity and Energy ConversionThermoelectric Figure of MeritOrigins of ThermoelectricityEffect of Nanostructuring on S2sAlloy limit of thermal conductivity in crystalline materials!Si/SiGe superlattice nanowiresErAs Nanostructures Embedded in InGaAsBelow Alloy Limit!HypothesisSi-Ge SuperlatticesSEM Picture of Thin Film Coolersn-Si/SiGeC Superlattice Micro CoolerMicro Refrigerator Integrated with Thin-Film HeaterInP-based Micro Refrigerator & Micro HeaterNanowire Array Composites and Devices