Near-Infrared Intersubband Absorption in MBE-Grown Lattice-Matched In AIN/GaN superlattices

Strong and direct near-infrared intersubband absorption is observed at room-temperature in silicon-doped lattice-matched InAlN/GaN superlattices grown by molecular beam epitaxy on GaN templates grown by hydride vapor-phase epitaxy. X-ray diffraction characterization of the heterostructures indicates excellent layer thickness uniformity and low interface roughness. For 2-4.5 nm quantum wells, the intersubband transition energies span the technologically relevant range between 2.3 and 2.9 Ým. The experimental results are in good agreement with calculations of the transition energies using a conduction band offset of 1 eV and spontaneous polarization of 3MV/cm.