The recombination-induced temperature change of non-equilibrium charge carriers

Publisher Website
Google Scholar
Abstract
A novel mechanism changing the temperature of a non-equilibrium gas of charge carriers is shown to exist: recombination of a proportion of the carriers. The rate of temperature change thus induced is proportional to the recombination probability 1/ tau . If recombination heating occurs it can compensate carrier-acoustic-phonon-mediated energy relaxation. For density- and time-independent recombination probabilities the minimum temperature Tmin that carriers can reach is defined. The sign, size and temperature dependence of the 'recombination heating' depend on the type of statistics obeyed by the carriers and on the details of the energy dependence of the recombination probability. For Maxwell-Boltzmann statistics heating, nothing or cooling occurs if the recombination probability decreases with, does not depend on or increases with energy, respectively. If the Fermi statistics applies to an electron-hole plasma the remaining carriers always heat upon recombination. The results of this theory are compared with experimental findings on the temperature relaxation of free electrons trapped by impurities, excitons in quantum wells and electron-hole drops.
Keywords