Near Field Photoluminescence Investigation of Surface Defects in InGaN/GaN Quantum Wells

Abstract

We used UV near-field scanning optical microscopy (NSOM) to investigate the photoluminescence characteristics of surface defects of blue emitting InGaN/GaN quantum wells. The result shows that the band-edge emission is higher around the perimeter of V-shaped defect, but is suppressed on the defects themselves. And the spectroscopic investigation of InGaN/GaN quantum wells with UV-NSOM showed that peak wavelength of PL spectra obtained from inside the V-shaped defectis different to those from outside the defect. These results can explain the broad PL curve in a defective sample. To study further the origin of the wavelength shift observed from the inside of the surface defects,we performed micro-Raman scattering and transmission electron microscopyexperiments.