نتایج جستجو برای: exciton binding energy
تعداد نتایج: 1067675 فیلتر نتایج به سال:
We calculate the optical absorption spectra of low-energy uncapped zinc sulfide nanostructures found by global optimisation (basin-hopping/simulated annealing) using time-dependent density functional theory (TD-DFT) and compare the results with experimental spectra. We predict that for all nanostructures studied the lowest excited state found by TD-DFT corresponds to an exciton with an exciton ...
Magnetic-field dependence of the spin states of the negatively charged exciton in GaAs quantum wells
We present high-field (,50 T) photoluminescence measurements of the binding energy of the singlet and triplet states of the negatively charged exciton in a 200-Å quantum well. Comparing our data with those of other groups and with theoretical predictions we clearly show how the singlet, ‘‘bright’’ and ‘‘dark’’ triplet states may be identified according to the high-field dependence of their bind...
Two-dimensional (2D) transition metal dichalcogenides (TMDs) are emerging as a new platform for exploring 2D semiconductor physics. Reduced screening in two dimensions results in markedly enhanced electron-electron interactions, which have been predicted to generate giant bandgap renormalization and excitonic effects. Here we present a rigorous experimental observation of extraordinarily large ...
The elementary optical excitations of a two-dimensional electron or hole system have been identified as exciton-Fermi-polarons. Nevertheless, the connection between bound state an exciton and electron, termed trion, exciton–polarons is subject ongoing debate. Here, we use analogy to Tavis–Cummings model quantum optics show that exciton–polaron can be understood hybrid quasiparticle—a coherent s...
We study exciton and biexciton spectra in disordered semiconductor quantum wires by means of nanophotoluminescence spectroscopy. We demonstrate a close link between the exciton localization length along the wire and the occurrence of a biexciton spectral line. The biexciton signature appears only if the corresponding exciton state extends over more than a few tens of nanometers. We also measure...
We calculate the exciton binding energy in narrow band gap single-walled carbon nanotubes with and graphene nanoribbons, accounting for the quasi-relativistic dispersion of electrons and holes. Exact analytical solutions of the quantum relativistic two-body problem are obtained for several limiting cases. We show that the binding energy scales with the band gap, and conclude on the basis of the...
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