High-temperature luminescence in an $n$-GaSb/$n$-InGaAsSb/$p$-AlGaAsSb light-emitting heterostructure with a high potential barrier

The electroluminescent properties of an $n$-GaSb/$n$-InGaAsSb/$p$-AlGaAsSb heterostructure with a high potential barrier in the conduction band (large conduction-band offset) at the $n$-GaSb/$n$-InGaAsSb type-II heterointerface ($\Delta E_c$ = 0.79 eV) are studied. Two bands with peaks at 0.28 and 0.64 eV at 300 K, associated with radiative recombination in $n$-InGaAsSb and $n$-GaSb, respectively, are observed in the electroluminescence (EL) spectrum. In the entire temperature range under study, $T$ = 290–480 K, additional electron-hole pairs are formed in the $n$-InGaAsSb active region by impact ionization with hot electrons heated as a result of the conduction-band offset. These pairs contribute to radiative recombination, which leads to a nonlinear increase in the EL intensity and output optical power with increasing pump current. A superlinear increase in the emission power of the long-wavelength band is observed upon heating in the temperature range $T$ = 290–345 K, and a linear increase is observed at $T >$ 345 K. This work for the first time reports an increase in the emission power of a light-emitting diode structure with increasing temperature. It is shown that this rise is caused by a decrease in the threshold energy of the impact ionization due to narrowing of the band gap of the active region.