Advances in thermoelectric microcooling

As the rapidly increasing integration density of electronics, thermal management is becoming more rigorous for the reliability of microelectronic devices. Advanced thermoelectric microcooling technology is receiving more attention due to advantages, such as long lifetime, no moving parts, and etc. In the past 50 years, researchers have been searching for materials with high ZT. Quasicrystals, such as Al-based icosahedral quasicrystals, which possess peculiar electronic and thermal transport properties are considered to be the candidate for thermoelectric materials. While this work on new compounds is in progress, there have also been a number of attempts to produce thermoelectric materials in which at least one of the dimensions is not much greater than the lattice constant, such as superlattice, nanowire and quantum dot. In 1997, Shakouri and Bowers proposed thermionic emission cooling in heterostructures, in which a potential barrier was used for selective emission of hot electrons, and the evaporative cooling of the electron gas. It is expected that non-planar potential barrier could overcome the conservation of momentum that limits the efficiency of thermionic emission cooling for planar barrier.