Nonlinear anisotropic thermoelectric energy converter based on semiconductor films
St. Petersburg State University of Refrigeration and Food Engineering
Lomonosova St., 9, St. Petersburg 191002, Russia
The great success was achieved last years in development and technology of thermoelectric structures based on semiconductor’s thick and thin films. Unfortunately the problem of heat resistance in junctions always accompanies the usage of semiconductor films for thermoelectric energy converters.
The problem of junctions can be solved in so-called anisotropic thermoelement – a semiconductor single-crystal plate whose two opposite sides are maintained at different temperatures, and the direction of the hear flow does not coincide with main crystallographic axises. The anisotropic thermoelement must use materials with high anisotropy of thermoelectric properties but number of known materials with such properties is very limited.
In the present paper we suggest a nonlinear and nonlocal model of energy and electric transport in anisotropic media under extreme temperature conditions. We found out that crystal symmetry reduces if nonlinear and nonlocal transport effects realized; therefore semiconductors with a cubic crystal structure receive strong anisotropic properties. Hence cubic semiconductors can be used as a material for anisotropic thermoelectric energy converter. The thermoelectric voltage generated in nonlinear anisotropic thermoelement strongly increase with decrease of the semiconductor’s film thickness. Therefore the thermoelectric voltage can reach giant values in such energy converters based on film cubic materials like Si and Ge.