Growth of InGaN self-assembled quantum dots and their applicationto lasers

摘要

We have successfully grown InGaN self assembled quantum dotsn(QD's) on a GaN layer, using atmospheric-pressure metalorganic chemicalnvapor deposition (MOCVD). The average diameter of the QD's was as smallnas 8.4 nm, and strong emission from the QD's was observed at roomntemperature. Next, we have investigated a structure in which InGaN QD'snwere stacked to increase the total QD density. InGaN QD's were formedneven when the number of stacked layers was ten. As the number of layersnincreased, the photoluminescence (PL) intensity increased drastically.nMoreover, we have fabricated a laser structure with InGaN QD's embeddedninto the active layer. A clear threshold of 6.0 mJ/cm2 wasnobserved in the dependence of the emission intensity on the excitationnenergy at room temperature under optical excitation. Above thenthreshold, the emission was strongly polarized in the transversenelectric (TE) mode, and the linewidth of the emission spectra wasnreduced to below 0.1 nm (resolution limit). The peak wavelength wasnaround 405 nm. These results indicate lasing action at room temperature