Two Biexciton Types Coexisting in Coupled Quantum Dot Molecules

Abstract

Coupled colloidal quantum dot molecules are an emerging class of nanomaterials, introducing new degrees of freedom for designing quantum dot-based technologies. The properties of multiply excited states in these materials are crucial to their performance as quantum light emitters but cannot be fully resolved by existing spectroscopic techniques. Here we study the characteristics of biexcitonic species, which represent a rich landscape of different configurations, such as segregated and localized biexciton states. To this end, we introduce an extension of Heralded Spectroscopy to resolve different biexciton species in the prototypical CdSe/CdS coupled quantum dot dimer system. We uncover the coexistence and interplay of two distinct biexciton species: A fast-decaying, strongly-interacting biexciton species, analogous to biexcitons in single quantum dots, and a long-lived, weakly-interacting species corresponding to two nearly-independent excitons separated to the two sides of the coupled quantum dot pair. The two biexciton types are consistent with numerical simulations, assigning the strongly-interacting species to two excitons localized at one side of the quantum dot molecule and the weakly-interacting species to excitons segregated to the two quantum dot molecule sides. This deeper understanding of multiply excited states in coupled quantum dot molecules can support the rational design of tunable single- or multiple-photon quantum emitters.

arXiv comment13 pages, 5 figures

References in corpus (13)

• Quantum Computation with Quantum Dots
• Colloidal Quantum Nanostructures: Emerging Materials for Display Applications
• Biexciton fine structure in monolayer transition metal dichalcogenides
• Coupled Colloidal Quantum Dot Molecules
• Perspective on Coupled Colloidal Quantum Dot Molecules
• Resolving the controversy in biexciton binding energy of cesium lead halide perovskite nanocrystals through heralded single-particle spectroscopy
• Heralded spectroscopy reveals exciton-exciton correlations in single colloidal quantum dots
• Electronic coupling in colloidal quantum dot molecules; The case of CdSe/CdS core/shell homodimers
• Deciphering Charging Status, Absolute Quantum Efficiency, and Absorption Cross Section of MultiCarrier States in Single Colloidal Quantum Dot
• Neck Barrier Engineering in Quantum Dot Dimer Molecules via Intra-Particle Ripening
• Semiconductor Bowtie Nanoantenna from Coupled Colloidal Quantum Dot Molecules
• Complete mapping of interacting charging states in single coupled colloidal quantum dot molecules
• Photon Correlations in Colloidal Quantum Dot Molecules Controlled by the Neck Barrier

Cited by in corpus (1)

• Trions Stimulate Electronic Coupling in Colloidal Quantum Dot Molecules