Negative thermal quenching in optically pumped GaAsBi–GaAs heterojunction p–i–n diode

We studied the electroluminescence (EL) properties of an optically pumped GaAsBi–GaAs heterojunction p–i–n diode. GaAsBi–GaAs quantum well excitonic transitions dominate the EL except at low temperatures, where the luminescence from Bi-induced localized states also influences the luminescence. When the diode is optically pumped, the EL exhibits negative thermal quenching, and for a certain range of optical pump powers, we obtained the room-temperature EL intensity higher than that at the lowest temperature (22 K). We explain this by considering the thermally induced tunneling of photo-generated carriers from the n+ and p+ regions into the GaAsBi QW in the i-region of the p–i–n diode.