SUPPRESSION OF NON-RADIATIVE RECOMBINATION IN MATERIALS WITH DEEP CENTRES

摘要

Procedure to obtain semiconductor materials with electronic levels close to the mid-bandgap (deep levels) which do not suffer from the non-radiative recombination by multiple phonon emission (MPE) associated to the existence of that kind of levels. The procedure consist in doping by any means the semiconductor with a density sufficiently high of the impurities producing the deep level, so that a Mott transition of the electron wavefunctions representing the localized states in the impurities is induced, in such a way that these wavefunctions become distributed across the whole semiconductor and are shared by all the impurities. When this happens, local charge density variations, and thus non-radiative recombination by MPE, disappear. Based on the resulting materials (semiconductors with three separate energy bands and radiative behavior (1), (2) and (3)) different optoelectronic devices can be fabricated (solar cells, photodetectors, lasers, etc.) capable of using electronic radiative transitions more efficiently.