Analysis of light-emission enhancement of low-efficiency quantum dots by plasmonic nano-particle.

In this paper, a nano-pillar array integrated near quantum dots (QDs), which serves as a Purcell cavity as well as a column antenna, is studied in order to enhance the spontaneous emission (SE) rate of low emission efficiency QDs. A systematic analysis for treating the isolated nano-pillar and loose ordered pillar is demonstrated by solving the electromagnetic field equations. As an illustrative example of potential applications, we proposed a new structure that Germanium (Ge) QDs are located in close proximity to the isolated Indium Tin Oxide (ITO) nano-pillar to raise its efficiency. From the results of numerical calculation, it is predicted that ITO pillars with slim (e.g., the radius is 25 nm and the height is 500 nm) and flat morphology (e.g., the radius is 40 nm and the height is 60 nm) exhibit superior enhancement over 20 folds. Finite difference time domain (FDTD) simulation is utilized for demonstrating the distinctive enhancement when QDs radiate at surface plasmonic resonance frequency of ITO nano-pillar. It can be found that the QDs emission enhancement profile accords with our results obtained from numerical analysis.