Field-effect induced mid-infrared intersubband electroluminescence of quantum wire cascade structures

Employing the Cleaved Edge Overgrowth technique, GaAs/AlGaAs quantum wire cascade structures have been fabricated. The quantum wire states are formed by the perpendicular overlap of two confinement potentials, one resulting from a strong potential modulation generated by quantum wells along the [001]-crystal direction, and a second resulting from an additional in-plane confinement generated by a silicon-delta-doping along the [110]-crystal direction. Radiative electronic transitions between discrete energy levels in coupled quantum wires are predicted in these samples. Above a threshold of 200 mA, mid-infrared electroluminescence is observed at an energy of 150 meV. The devices were temperature controlled at 20K. The emission intensity is clearly current dependent and rises linearly with a slope efficiency of 0.1 nW/mA up to a maximum output power of 17 nW.