Photoluminescence of patterned arrays of vertically stacked InAs/GaAs quantum dots

We report on photoluminescence measurements of vertically stacked InAs/GaAs quantum dots grown by molecular beam epitaxy on focused ion beam patterned hole arrays with varying array spacing. Quantum dot emission at 1.24 eV was observed only on patterned regions, demonstrating preferential nucleation of optically active dots at desired locations and below the critical thickness for dot formation at these growth conditions. Photoluminescence measurements as a function of varying focused ion beam irradiated hole spacing showed that the quantum dot emission intensity increased with decreasing array periodicity, consistent with increasing dot density.