Ground-state exciton emission of InAs quantum dots produced by focused-ion-beam-directed nucleation

► Single quantum dots are patterned in a 2-dimensional lattice by a focused ion beam. ► Single dot emission linewidth as narrow as 160 μeV is observed. ► Spatially mapped photoluminescence gives the site-selective spectrum of the dots. ► A power dependence shows that peaks are from ground-state excitons of different dots.