Progress in GaN-based nanostructures for blue light emitting quantum dot lasers and vertical cavity surface emitting lasers

Our recent progress in GaN-based nanostructures for quantum dot (QD) lasers and vertical microcavity surface emitting lasers (VCSELs) is discussed. We have grown InGaN self-assembled QDs on a GaN epitaxial layer, using atmosp heric-pressure metalorganic chemical vapor deposition. The average diameter of the QDs was as small as 8.4 nm and strong photoluminescence emission fr om the QDs was observed at room temperature. Furthermore, we found that InG aN QDs could he formed even after 10 QD layers were stacked, thus increasin g the total QD density. Using these growth results, we fabricated a laser s tructure with InGaN QDs embedded in the active layer. A clear threshold was observed in the dependence of the emission intensity on the excitation ene rgy at room temperature under optical excitation. We succeeded in demonstra ting in lasing action in vertical cavity surface emitting lasers at room te mperature with a cavity finesse of over 200.