High photon extraction efficiency from GaAs pillar with InAs quantum dots embedded in Niobium

We studied the novel structure for improving the emission properties of semiconductor light sources both theoretically and experimentally. The proposed structure is a semiconductor pillar buried in a metal except for one end surface of the pillar. Photons are extracted only from the air-exposed surface. The structure consists of the GaAs nanopillar structures embedded in metal and is analyzed by the finite-difference-time-domain method. InAs quantum dots buried in a GaAs pillar are assumed to be the photon emitters. Simulations are performed on GaAs pillars with different diameters buried in Niobium. Consequently, the simulation showed 75% light extraction efficiency from the pillar to air with the optimization of the structure. In addition, we experimentally measured photoluminescence intensities of up to 40 times enhancement in embedded structures compared to normal pillar structure. These are promising for future applications to overcome single photon sources.