Mid-Infrared Intersubband Absorption In Strain-Balanced Non-Polar (In)Algan/Ingan Multi-Quantum Wells

Mid-infrared intersubband transitions in strain-balanced m-plane (In)AlxGa1-xN/In0.16Ga0.84N (0.19 <= x <= 0.3) multi-quantum wells are reported for the first time in the range of 3.4-5.1 mu m (244-360 meV). Direct and attenuated total-reflection infrared absorption measurements are interpreted using structural information revealed by high-resolution x-ray diffraction and transmission electron microanalysis. The experimental intersubband energies are better reproduced by calculations using the local-density approximation than the Hartree-Fock approximation for the exchange-correlation correction. The effect of charge density, quantum well width, and barrier alloy composition on the intersubband transition energy is also investigated to evaluate the potential of this material for practical device applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement