Observation of intersubband transition at 1.2～1.6μm optical communication wavelength in AlN/GaN superlattices

摘要

Intersubband transition (ISBT) at the optical communication wavelength range from 1.14 to 1.61 μm was systematically investigated in (GaN)m/(AlN)n superlattices (SIs). The SL samples were grown directly on (0001) sapphire substrates by molecular beam epitaxy using rf-plasma nitrogen as a source (rf-MBE). The Ss consisted of 90 periods of GaN-well (m=2～10 mono-layer (ML) in thickness) and AlN barrier (n～11 ML). For a 4-ML GaN well, the ISBT absorption wavelength reached down to 1.14 μm, close to a theoretically predicted limitation, and it was shifted monotonically up to 1.6 μm with increasing the well thickness to 9.5 ML. The linewidth of the absorption spectra as narrow as 61 meV was observed 1.54 μm.