Photoluminescence from sub-nanometer-thick GaN/Al0.8Ga0.2N quantum wells

Photoluminescence (PL) spectra were measured for sub-nanometer-thick GaN quantum wells (QWs) with ${\mathrm{Al}}_{\mathrm{0.8}}{\mathrm{Ga}}_{\mathrm{0.2}}\mathrm{N}$ barriers, which were grown by atmospheric-pressure metal–organic chemical-vapor deposition. The thickness of the GaN QW layers was systematically varied from 1 to 4 ML. We clearly observed a PL peak at room temperature at a wavelength as short as 247 nm (5.03 eV) from 1-ML-thick QWs. The effective confinement energy, or difference between this recombination energy and the band gap of bulk GaN, is as large as 1.63 eV.