Massachusetts Institute of Technology

University of California

Takaaki Koga

Mildred S Dresselhaus

Xiangzhong Sun

Theodore C Harman

Stephen B Cronin

Kang L Wang

Michael P Walsh

David L Spears

Steven B Cronin

A carrier pocket engineering technique used to provide superlattice structures having relatively high values of the three-dimensional thermoelectric figure of merit (Z T) is described. Also described are several superlattice systems provided in acordance with the carrier pocket engineering technique. Superlattice structures designed in accordance with this technique include a plurality of alternating layers of at least two different semiconductor materials. First ones of the layers correspond to barrier layers and second ones of the layers correspond to well layers but barrier layers can also work as well layers for some certain carrier pockets and vice-versa. Each of the well layers are provided having quantum well states formed from carrier pockets at various high symmetry points in the Brillouin zone of the structure to provide the superlattice having a relatively high three-dimensional thermoelectric figure of merit.

Superlattice structures having selected carrier pockets and related methods

A superlattice structure for thermoelectric power generation includes m monolayers of a first barrier material alternating with n monolayers of a second quantum well material with a pair of monolayers defining a superlattice period and each of the materials having a relatively smooth interface therebetween. Each of the quantum well layers have a thickness which is less than the thickness of the barrier layer by an amount which causes substantial confinement of conduction carriers to the quantum well layer and the alternating layers provide a superlattice structure having a figure of merit which increases with increasing temperature.

Superlattice structures for use in thermoelectric devices

A superlattice structure for use in thermoelectric power generation systems includes m layers of a first one of Silicon and Antimony doped Silicon-Germanium alternating with n layers of Silicon-Germanium which provides a superlattice structure having a thermoelectric figure of merit which increases with increasing temperature above the maximum thermoelectric figure of merit achievable for bulk SiGe alloys.

Si/SiGe superlattice structures for use in thermoelectric devices

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Kawagoo, Japan

Takaaki Koga