Bistability of electroluminescence in a type-II AlGaAsSb/InGaAsSb double heterostructure

Electroluminescence bistability is observed in a typ-II P-AlGaAsSb/p-InGaAs Sb/ N-AlGaAsSbheterostructure with lightly doped cladding layers and a narr ow-gap active region (the width of the band gap is E-g=326 meV at the tempe rature T=77 K). A current-controlled negative differential resistance is ob served in the forward branch of the current-voltage characteristic. Strong narrowband electroluminescence (half-width similar to 7-10 meV) is observed at the end of the negative differential resistance interval, where the pho ton energy at the radiation maximum exceeds the width of the band gap of th e narrow-gap material by 50 meV. This phenomenon is attributed to the tunne ling injection and indirect radiative recombination of carriers localized a t the AlGaAsSb/InGaAsSb heterojunction. As the voltage is increased, radiat ive transitions in the bulk of the active region begin to provide the main contribution, and the radiation maximum jumps to the long-wavelength end. T unneling injection structures of this kind can be used to construct highly efficient current-controlled light-emitting diodes. (C) 1999 American Insti tute of Physics. [S1063-7826(99)02203-6].