Quantum-dot-like composition fluctuations in near-field magneto-photoliminescence [photoluminescence] spectra of InGaAsN alloys

A series of narrow emission lines (halfwidth 0.5-2 meV) corresponding to quantum-dot-like compositional fluctuations have been observed in low temperature near-field photoluminescence spectra of GaAsN and InGaAsN alloys. The estimation of the size, density, and nitrogen excess of individual compositional fluctuations (clusters) using scanning near-field magneto-spectroscopy reveals phase-separation effects in the distribution of nitrogen. We found a strong effect of In on the exciton g-factor in InGaAsN alloys.