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Solid-State and Vacuum Thermionic Energy Conversion

Published online by Cambridge University Press:  01 February 2011

Ali Shakouri
Affiliation:
ali@soe.ucsc.edu, University of California at Santa Cruz, Electrical Engineering, Baskin School of Engineering, SOE2, Santa Cruz, CA, 95064, United States
Z. Bian
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
R. Singh
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
Y. Zhang
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
D. Vashaee
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
T. E. Humphrey
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
H. Schmidt
Affiliation:
Baskin School of Engineering, University of California at Santa Cruz
J. M. Zide
Affiliation:
Materials Department, Electrical and Computer Engineering, University of California at Santa Barbara
G. Zeng
Affiliation:
Materials Department, Electrical and Computer Engineering, University of California at Santa Barbara
J-H. Bahk
Affiliation:
Materials Department, Electrical and Computer Engineering, University of California at Santa Barbara
A. C. Gossard
Affiliation:
Materials Department, Electrical and Computer Engineering, University of California at Santa Barbara
J. E. Bowers
Affiliation:
Materials Department, Electrical and Computer Engineering, University of California at Santa Barbara
V. Rawat
Affiliation:
Materials Engineering, Electrical and Computer Engineering, Purdue University
T. D. Sands
Affiliation:
Materials Engineering, Electrical and Computer Engineering, Purdue University
W. Kim
Affiliation:
Mechanical Engineering Department, University of California at Berkeley
S. Singer
Affiliation:
Mechanical Engineering Department, University of California at Berkeley
A. Majumdar
Affiliation:
Mechanical Engineering Department, University of California at Berkeley
P. M. Mayer
Affiliation:
Research Laboratory of Electronics, Massachusetts Institute of Technology
R. J. Ram
Affiliation:
Research Laboratory of Electronics, Massachusetts Institute of Technology
K. J. Russel
Affiliation:
Division of Engineering and Applied Sciences, Harvard University
V. Narayanamurti
Affiliation:
Division of Engineering and Applied Sciences, Harvard University
F. A. M. Koeck
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
X. Li
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
J.-S. Park
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
J. R. Smith
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
G. L. Bilbro
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
R. F. Davis
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
Z. Sitar
Affiliation:
Departments of Physics, Materials Science and Engineering and Electrical and Computer Eng., North Carolina State University
R. J. Nemanich
Affiliation:
Robert_Nemanich@ncsu.edu, North Carolina State University, Physics Department, United States
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Abstract

A brief overview of the research activities at the Thermionic Energy Conversion (TEC) Center is given. The goal is to achieve direct thermal to electric energy conversion with >20% efficiency and >1W/cm2 power density at a hot side temperature of 300–650C. Thermionic emission in both vacuum and solid-state devices is investigated. In the case of solid-state devices, hot electron filtering using heterostructure barriers is used to increase the thermoelectric power factor. In order to study electron transport above the barriers and lateral momentum conservation in thermionic emission process, the current-voltage characteristic of ballistic transistor structures is investigated. Embedded ErAs nanoparticles and metal/semiconductor multilayers are used to reduce the lattice thermal conductivity. Cross-plane thermoelectric properties and the effective ZT of the thin film are analyzed using the transient Harman technique. Integrated circuit fabrication techniques are used to transfer the n- and p-type thin films on AlN substrates and make power generation modules with hundreds of thin film elements. For vacuum devices, nitrogen-doped diamond and carbon nanotubes are studied for emitters. Sb-doped highly oriented diamond and low electron affinity AlGaN are investigated for collectors. Work functions below 1.6eV and vacuum thermionic power generation at temperatures below 700C have been demonstrated.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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References

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