Near-field photoluminescence imaging of single semiconductor quantum constituents with a spatial resolution of 30 nm

High-resolution photoluminescence (PL) imaging of semiconductor quantum dots (QDs) was demonstrated using a low-temperature near-field scanning optical microscope. We systematically evaluated the spatial resolution for various fiber probes with different aperture diameters ranging from 30 to 135 nm. We achieved a spatial resolution of 30 nm (∼λ/30:λ=930 nm) in the PL imaging of self-assembled InAs QDs due to both improvement in probe preparation and optimization of the sample structure. The spatial resolution obtained in this study is on the scale of semiconductor quantum constituents and will make it possible to map out and manipulate the wave function in quantum-confined systems.