Light emission from individual self-assembled InAs/GaAs quantum dots excited by tunneling current injection

We report emission from individual quantum dots excited by tunneling current injection using a scanning tunneling microscope (STM). By scanning the STM tip above the self-assembled InAs quantum dots, a spatially resolved scanning tunneling luminescence (STL) image was measured, which contained a fluorescent circular region with a diameter of 50 nm originating from a single InAs quantum dot. It was found that the spatial resolution of the STL system was about 40 nm, which is mainly due to lateral diffusion of holes injected into a GaAs capping layer grown at low temperature (480 °C). We also obtained STL spectra with a sharp single luminescent peak from a single InAs quantum dot.