Coupling the graphene plasmonic with terahertz emission of truncated conic-shaped InAs/GaAs quantum dots: A passive approach to enhance the intersubband optical properties

Abstract

Graphene plasmonic (GP) concentrates the electromagnetic waves in small zones beyond the optical diffraction limit. This effect provides strong interactions of radiation with atomic and molecular systems in the vicinity. Here, in this work, we use GP effect to enhance the intersubband optical response of truncated conic-shaped InAs/GaAs quantum dots (QDs) attached to wetting layer (WL). Monolayer graphene flakes with triangular geometries arranged in various configurations are located in the QDs to intensify the electric field and consequently to couple GP with terahertz radiation of QDs. The results show 120-fold enhancement in S-to-P transition dipole moment (TDM) and 1.3 × 10 4 and 6.5 × 10 7 times enhancements, respectively, in the linear and third-order optical susceptibility of QDs. The optimal QDs are those with height of 5 nm and base length of 10 nm. The results of this work are promising to improve the performance of QD-based lasers, detectors, light emitting diodes (LEDs), etc. • Graphene flakes in triangular geometry have been placed in trancated conic-shaped InAs/GaAS quantum dots (QDs). • The emission of QDs has been tuned with graphene plasmonic (GP). • With use of GP effect, S-to-P transition dipole moment (TDM) of QD has been enhanced 120 times. • Linear susceptibility of QD has been multiplied by a factor of 1.3 × 10 4 . • Third-order susceptibility of QD has been multiplied by a factor of 6.5 × 10 7 .