Polarized emission lines from A- and B-type excitonic complexes in single InGaN/GaN quantum dots

Cathodoluminescence measurements on single InGaN/GaN quantum dots (QDs) are reported. Complex spectra with up to five emission lines per QD are observed. The lines are polarized along the orthogonal crystal directions [1 1 -2 0] and [-1 1 0 0]. Realistic eight-band k.p electronic structure calculations show that the polarization of the lines can be explained by excitonic recombinations involving hole states which are either formed by the A or the B valence band.