Analysis and characterization of thermoelectric microrefrigerators

Abstract

Advances in film growth techniques have sparked a renewed interest in thermoelectric (TE) devices. A previous study suggested that a drastic improvement in the figure of merit can be achieved for superlattices and quantum wells by exploiting phonon scattering/reflection at interfaces or carrier pocket engineerin. Thin-film devices are also of great significance because of their capability to handle considerably higher heat flux than conventional bulk modules. Microrefrigerators consist of a single or multiple thin-film thermoelement(s). The use of thin films introduces the full complexity of solid-solid interfaces into any complete discussion of these refrigerators. Many investigators noted that the electrical contact resistance has adverse effects on TE cooling. Less attention has been paid to thermal interface resistance and the boundary Seebeck effects. While previous studies [4] have indicated that the interface effects are related to each other via boundary forms of the Wiedemann-Franz-Lorenz law and the Kelvin-Onsager relation, the impact of their mutual interactions on thermoelectric cooling has remained relatively unexplored.