Bound electron–hole pairs—excitons—are light Bose particles with a mass comparable to or smaller than that of the free electron. Since the quantum degeneracy temperature scales inversely with the mass, it is anticipated that Bose–Einstein condensation of an exciton gas can be achieved at temperatures of about 1 K, orders of magnitude larger than the micro-Kelvin temperatures employed in atomic ...

Exciton binding energy and excited states in monolayers of tungsten diselenide (WSe(2)) are investigated using the combined linear absorption and two-photon photoluminescence excitation spectroscopy. The exciton binding energy is determined to be 0.37 eV, which is about an order of magnitude larger than that in III-V semiconductor quantum wells and renders the exciton excited states observable ...

The coupling of excitons with phonons is an important process determining the mechanism of exciton transport in molecular crystals. Although linear exciton-phonon coupling has been extensively treated before, there has been little work on quadratic coupling. In this paper the theory of exciton transport is extended to take weak quadratic coupling into account, and the diffusion constant compute...

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Experimentally observed two-exponential decay of excitonic transitions in GaAs-Al Gal — As multiple quantum wells has been successfully interpreted in terms of the exciton transfer between the continuum (free carriers) and the bound states. The calculation results obtained from this exciton-transfer model are in excellent agreement with experimental observations. The rates of the exciton transf...

A Mach-Zehnder interferometer with spatial and spectral resolution was used to probe spontaneous coherence in cold exciton gases, which are implemented experimentally in the ring of indirect excitons in coupled quantum wells. A strong enhancement of the exciton coherence length is observed at temperatures below a few Kelvin. The increase of the coherence length is correlated with the macroscopi...

We examine exciton recombination, energy-, and charge transfer in multilayer CdS/ZnS quantum dots (QDs) on silver plasmonic resonators using photoluminescence (PL) and excitation spectroscopy along with kinetic modeling and simulations. The exciton dynamics including all the processes are strongly affected by the separation distance between QDs and silver resonators, excitation wavelength, and ...

Effective tight-binding models have been introduced to describe vertical electronic excitations in branched conjugated molecules. The excited-state electronic structure is characterized by quantum particles (excitons) that reside on an irregular lattice (graph) that reflects the molecular structure. The methodology allows for the exciton spectra and energy-dependent exciton scattering matrices ...

We present an experimental investigation on the exciton dynamics of monolayer and bulk WSe2 samples, both of which are studied by femtosecond transient absorption microscopy. Under the excitation of a 405 nm pump pulse, the differential reflection signal of a probe pulse (tuned to the A-exciton resonance) reaches a peak rapidly that indicates an ultrafast formation process of excitons. By resol...