Detecting spatially localized excitons in InGaN quantum well structures with a micro-photoluminescence technique

摘要

Spatially localized excitons are observed in InGaN quantum well structures at 4 K by using a micro-photo luminescence (PL) technique. By combining PL and nano-lithographic techniques, we are able to detect PL signals with a 0.2 mu m spatial resolution. A sharp PL line (linewidth of < 0.4 meV) is clearly obtained, which originates from a single localized exciton induced by a quantum dot like a local potential minimum position. Sharp PL spectra detected in three QWs with different indium compositions confirm that there are exciton localization effects in quantum wells in the blue-green (about 2.60 eV, 477 nm) to purple (about 3.05 eV, 406 nm) regions. (c) 2006 Elsevier Ltd. All rights reserved.