Intersubband electroluminescence using X-Gamma carrier injection in a GaAs/AlAs superlattice

We report midinfrared electroluminescence originated from an intersubband t ransition in a GaAs/AlAs superlattice consisting of asymmetric double quant um wells. It is confirmed from interband photoluminescence properties under applied bias voltages that electrons populate at the second Gamma (Gamma 2 ) subband in the GaAs layer. The electron population results from the carri er injection into the Gamma 2 subband from the adjacent X1 subband in the A lAs layer, which is initiated by the X1-Gamma 2 resonance. The energy of th e intersubband electroluminescence, 190 meV, agrees with the energy spacing between the Gamma 2 and Gamma 1 subbands. This demonstrates that the carri er injection into the higher Gamma subband using X-Gamma scattering is usef ul for the design of intersubband-emission devices. (C) 2000 American Insti tute of Physics. [S0003-6951(00)03632-9].