Heralded spectroscopy reveals exciton-exciton correlations in single colloidal quantum dots

Abstract

Multiply-excited states in semiconductor quantum dots feature intriguing physics and play a crucial role in nanocrystal-based technologies. While photoluminescence provides a natural probe to investigate these states, room temperature single-particle spectroscopy of their emission has so far proved elusive due to the temporal and spectral overlap with emission from the singly-excited and charged states. Here we introduce biexciton heralded spectroscopy, enabled by a single-photon avalanche diode array based spectrometer. This allows us to directly observe biexciton-exciton emission cascades and measure the biexciton binding energy of single quantum dots at room temperature, even though it is well below the scale of thermal broadening and spectral diffusion. Furthermore, we uncover correlations hitherto masked in ensembles, of the biexciton binding energy with both charge-carrier confinement and fluctuations of the local electrostatic potential. Heralded spectroscopy has the potential of greatly extending our understanding of charge-carrier dynamics in multielectron systems and of parallelization of quantum optics protocols.

9+10 pages, 5+8 figures

References in corpus (2)

• Entangled Photon Pairs from Semiconductor Quantum Dots
• Quantum correlation measurement with single photon avalanche diode arrays

Cited by in corpus (8)

• Resolving the controversy in biexciton binding energy of cesium lead halide perovskite nanocrystals through heralded single-particle spectroscopy
• Intensified Tpx3Cam, a fast data-driven optical camera with nanosecond timing resolution for single photon detection in quantum applications
• Two Biexciton Types Coexisting in Coupled Quantum Dot Molecules
• Photon Correlations in Colloidal Quantum Dot Molecules Controlled by the Neck Barrier
• Electric-field fluctuations as the cause of spectral instabilities in colloidal quantum dots
• Fast data-driven spectrometer with direct measurement of time and frequency for multiple single photons
• Resolving the emission transition dipole moments of single doubly-excited seeded nanorods via heralded defocused imaging
• Vanishing quantum confinement enables bright and thermally excited multi-carrier emission from semiconductor nanocrystals