Laser Cooling in Semiconductor Heterojunctions by Extraction of Photogenerated Carriers

η rad φ in (E) Laser cooling of a semiconductor material, in which heat is extracted by emitting photons, requires a near-perfect external radiative efficiency. In this theoretical work, we propose a cooling system based on carrier extraction in a large gap reservoir. The electron-hole pairs generated in the material to be cooled are extracted in such a reservoir by absorbing phonons, then carrying a heat flux. With an analytical detailed balance model, we show that this concept is applicable even in materials with moderate external radiative efficiency. Moreover, by adjusting the gap of the reservoir to the laser power, this system can either reach high efficiency or transfer high power with lower efficiency