Type II Superlattice as Low-Temperature Peltier Refrigerator (4K-150K)
Abstract
We developed a new paradigm for thermoelectric cooling which we call anisotropic ambipolar transverse thermoelectrics (AATT), whereby both electrons and holes conduct simultaneously, but n-type in one direction and p-type orthogonal. When an electric field is applied at 45 degrees to these axes, electrical current flows perpendicular to a heat current. Transverse thermoelectrics have the advantage that an exponentially tapered devices function as infinite stage thermoelectric cascades, allowing arbitrarily low temperature cooling regardless of the figure of merit ZT. The Type II superlattice of InAs/GaSb is shown to be an example AATT material. The thermal conductivity was experimentally measured, and the electrical resistance and Seebeck tensor were theoretically calculated. Transverse thermoelectrics allow cryogenic cooling, and nanoscale thermoelectric devices. Thin-film metallic thermocouples of nickel and chromium were fabricated and tested in order to calibrate thermal gradients. The devices gave reproducible linear Seebeck effect at about the bulk Seebeck coefficient for these materials. Patents are pending for both the thin-film thermocouple technology and the AATT transverse thermoelectrics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 29, 2012
- Accession Number
- ADA565302
Entities
People
- Gerhard Abstreiter
- Gregor Koblmueller
- Matthew Grayson
- Seda Memik
Organizations
- Northwestern University