Impact of Nitrogen incorporation on pseudomorphic site-controlled quantum dots grown by Metalorganic Vapour Phase Epitaxy

We report on some surprising optical properties of diluted nitride InGaAs_(1-y)N_y /GaAs (y<<1) pyramidal site-controlled quantum dots, grown by metalorganic vapor phase epitaxy on patterned GaAs (111)B substrates. Microphotoluminescence characterizations showed antibinding exciton/ biexciton behavior, a spread of exciton lifetimes in an otherwise very uniform sample, with unexpected long neutral exciton lifetimes (up to 7 ns) and a nearly zero fine structure splitting on a majority of dots.