Electroluminescence cooling in semiconductors

Fundamental mechanisms of electroluminescence refrigeration in heterostructure light-emitting diodes

“…Laser pumped optical cooling has been demonstrated in rare-earth doped glasses with a temperature drop up to 90 K from room temperature. 1,2 Compared with rare-earth doped glasses, semiconductor optical refrigerators are expected to offer one order of magnitude lower working temperatures 3 and can be pumped either optically [3][4][5] or electrically [6][7][8][9] . Electrical injection is more straightforward to implement than optical pumping for practical applications.…”

“…Electroluminescence (EL) refrigeration in light emitting diodes (LED) has been studied theoretically [6][7][8][9] from an energy conservation point of view, where the energy difference between the optical output and the electrical input is attributed to the absorption of lattice thermal energy by the electrons and holes, which is subsequently carried away by photon emission. The conventional drift-diffusion model used in previous LED work assumes an ohmic contact boundary condition at the metal/semiconductor interface; this implies that the carriers are in thermal equilibrium with the lattice, and hence overlooks the energy exchange process (thermoelectric cooling) between the carriers and the semiconductor lattice during injection.…”