Enhanced Quantum Dot Light Emission at Telecom Wavelengths on Metallic Mirrors

Abstract

We demonstrate the integration of molecular beam epitaxy (MBE)-grown InP-based quantum dots (QDs) on gold thin films, achieving a fivefold enhancement of emission at telecom wavelengths compared with QDs grown on distributed Bragg reflectors (DBRs). Micro-photoluminescence (µ-PL) spectroscopy reveals a pronounced enhancement of the PL intensity, which is attributed to plasmon-assisted light–matter interaction at the metal–semiconductor interface. Reflectivity measurements reveal a characteristic dip near the QD emission wavelength, consistent with the excitation of surface plasmon resonances (SPRs), indicating favorable spectral overlap between the plasmonic modes and the QD emission. Power-dependent measurements reveal background-free exciton and biexciton emission from single QDs with resolution-limited linewidths. Polarization-dependent measurements demonstrate an ultra-small excitonic fine-structure splitting as low as ~2 μeV. Finally, a statistical analysis of multiple QDs confirms the reproducibility of the observed optical properties.