Localized high-energy emissions from the vicinity of defects in high-efficiency GaxIn1-xN/GaN quantum wells -: art. no. 081309

Using a high-resolution low-temperature spectroscopic scanning near-field optical microscope we observe highly localized high-energy emissions from highly efficient GaxIn1-xN/GaN quantum wells. These sharp emissions about 300-400 meV above the main quantum well luminescence are characteristic for high-efficiency structures and originate from the immediate vicinity of threading dislocations. Thus, areas of increased bandgap surrounding the defects appear to exist only in high-efficiency structures, which act as barriers prohibiting carriers from recombining nonradiatively at the defects.