The Origin of Quantum Effects in Low-Dimensional Thermoelectric Materials

Thermoelectric material, which directly converts waste heat to electricity, provides an ecofriendly power generator to reuse heat energy sources. New attempts have started for thermoelectricity of low-dimensional materials since 1993 when the theory of confinement effect was presented by Hicks and Dresselhaus. Experimental works have been inspired by the theory of confinement to the use of low-dimensional materials for improving thermoelectric efficiency for more than two decades. In this report, it is considered how recent theories and experiments have made progress on the quantum confinement effects. In particular, the reason is explained why the thermal de Broglie wavelength becomes a key parameter to enhance the power factor.