Intraband emission at λ≈1.48 μm from GaN/AlN quantum dots at room temperature

We report on the intraband emission at room temperature from GaN/AlN quantum dots grown by plasma-assisted molecular-beam epitaxy. The dots exhibit TM-polarized absorption ascribed to the intraband transition from the s to the p_z shells. The p_z-s intraband luminescence is observed at λ=1.48 μm under optical excitation at λ=1.34 μm perpendicular to the [0001] growth axis. The population of the p_z state arises from Raman scattering by GaN A₁ longitudinal optical phonons. Based on the emission spectral shape, we estimate that the homogeneous linewidth of the s-p_z intraband transition is less than 4 meV.