Power Factor Enhancement by Modulation Doping in Bulk Nanocomposites

We introduce the concept of modulation doping in three-dimensional nanostructured bulk materials to increase the thermoelectric figure of merit. Modulation-doped samples are made of two types of nanograins (a two-phase composite), where dopants are incorporated only into one type. By band engineerin...

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Bibliographic Details
Published in:Nano letters 2011-06, Vol.11 (6), p.2225-2230
Main Authors: Zebarjadi, Mona, Joshi, Giri, Zhu, Gaohua, Yu, Bo, Minnich, Austin, Lan, Yucheng, Wang, Xiaowei, Dresselhaus, Mildred, Ren, Zhifeng, Chen, Gang
Format: Article
Language:English
Subjects:
Boron - chemistry
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Cross-disciplinary physics: materials science
rheology
Electric Conductivity
Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures
Electronic transport in multilayers, nanoscale materials and structures
Exact sciences and technology
Germanium - chemistry
Materials science
Nanocomposites - chemistry
Nanocrystalline materials
Nanoscale materials and structures: fabrication and characterization
Physics
Silicon - chemistry
solar (photovoltaic), solar (thermal), solid state lighting, phonons, thermal conductivity, thermoelectric, defects, mechanical behavior, charge transport, spin dynamics, materials and chemistry by design, optics, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)
Surface Properties
Temperature
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Summary:We introduce the concept of modulation doping in three-dimensional nanostructured bulk materials to increase the thermoelectric figure of merit. Modulation-doped samples are made of two types of nanograins (a two-phase composite), where dopants are incorporated only into one type. By band engineering, charge carriers could be separated from their parent grains and moved into undoped grains, which would result in enhanced mobility of the carriers in comparison to uniform doping due to a reduction of ionized impurity scattering. The electrical conductivity of the two-phase composite can exceed that of the individual components, leading to a higher power factor. We here demonstrate the concept via experiment using composites made of doped silicon nanograins and intrinsic silicon germanium grains.
ISSN:1530-6984
1530-6992
DOI:10.1021/nl201206d