Annealing of GaN-InGaN multi quantum wells: Correlation between the bandgap and yellow photoluminescence

We report experimental data on photoluminescence (PL) annealing of metalorg anic chemical vapor deposition (MOCVD) grown GaN-InGaN multi quantum wells (MQWs). The formation of phase separation in the InGaN quantum well layer w as confirmed by PL mapping when the MQW was grown at 675 degrees C. Spatial distribution of the yellow (Y)-band PL correlated with the dislocation net work in that the intensity of the PL was lowest at the grain boundaries. Th e activation energy of thermal quenching of the InGaN PL at 400 nm was foun d to be equal to that of the increase of Y-band PL at 550 nm. The origin of the Y-band is explained as a radiative donor-acceptor recombination.