Room-temperature, mid-infrared (λ=4.7μm) electroluminescence from single-stage intersubband GaAs-based edge emitters

Abstract

GaAs -based, single-stage, intersubband devices with active regions composed of deep quantum wells (i.e., In0.3Ga0.7As) and high AlGaAs barriers display strong room-temperature emission at λ=4.7μm. The structures are grown by metalorganic chemical vapor deposition. The large energy barriers (∼360meV) for electrons in the upper energy level of the active region strongly suppress both the carrier leakage as well as the tunneling escape rate out of the wells. As a result, the ratio of emissions at 80 and 300K is as low as 2.0, and thus there is considerably less need for a Bragg mirror/transmitter-type region. Devices with virtually 100% tunneling injection efficiency have been realized, and their room-temperature spectra are narrow: 25meV full width at half maximum. These deep-well, single-stage structures are intended for use as the emitting units in two-dimensional, intersubband quantum-box lasers, or as the stages of quantum-cascade lasers for efficient, room-temperature operation in the 3–5-μm wavelength range.