Using a high-resolution low-temperature spectroscopic scanning near-field optical microscope highly localized high-energy emissions from highly efficient GaxIn1–xN/GaN quantum wells were observed. These sharp emissions, at 300 to 400meV above the main quantum well luminescence, were characteristic of high-efficiency structures and originated from the immediate vicinity of threading dislocations. Thus, areas of increased band-gap surrounding the defects appeared to exist only in high-efficiency structures, which acted as barriers which prohibited carriers from recombining non-radiatively at the defects.

Localized High-Energy Emissions from the Vicinity of Defects in High-Efficiency GaxIn1–xN/GaN Quantum Wells. F.Hitzel, G.Klewer, S.Lahmann, U.Rossow, A.Hangleiter: Physical Review B, 2005, 72[8], 081309 (4pp)