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Enhanced Thermionic Emission Cooling in High Barrier Superlattice Heterostructures

Published online by Cambridge University Press:  10 February 2011

Ali Shakouri
Affiliation:
Jack Baskin School of Engineering, University of California, Santa Cruz, CA 95046
Chris LaBounty
Affiliation:
Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, ali@cse.ucsc.edu
Patrick Abraham
Affiliation:
Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, ali@cse.ucsc.edu
Joachim Piprek
Affiliation:
Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, ali@cse.ucsc.edu
John E. Bowers
Affiliation:
Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, ali@cse.ucsc.edu
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Abstract

Thermionic emission current in heterostructures can be used to enhance thermoelectric properties beyond what can be achieved with conventional bulk materials. The Bandgap discontinuity at the junction between two materials is used to selectively emit hot electrons over a barrier layer from cathode to anode. This evaporative cooling can be optimized at various temperatures by adjusting the barrier height and thickness. Theoretical and experimental results for nonisothermal thermionic emission in heterostructures are presented. Single stage InGaAsP-based heterostructure integrated thermionic (HIT) coolers are fabricated and characterized. Cooling on the order of a degree over one micron thick barriers has been observed. Nonisothermal transport in highly doped tall barrier superlattices is also investigated. An order of magnitude improvement in cooling efficiency is predicted for InAlAs/InP superlattices.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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