Enhancing Light Emission From Germanium Quantum Dots by Bowtie Antennas

Light emitters based on germanium quantum dots (QDs) coupled with array of gold bowtie nanoantennas are fabricated and characterized on silicon-on-insulator substrate. Enhanced luminescence from germanium QDs is observed at room temperature with a maximum enhancement factor of 4.2 at 1577 nm. The light emission enhancement is due to the strong interaction between localized plasmonic mode of bowtie antennas and nearby germanium QDs. The theoretical analyses show that only a small amount of germanium QDs are efficiently enhanced by localized plasmonic mode. The maximum quantum efficiency enhancement of single germanium QD is estimated to be more than two-orders of magnitude.