Photon echo in the ensemble of semiconductor quantum dots spread on a glass substrate

Quantum dots photoinduced charges dynamics – model of crystall lattice defects

“…Nevertheless, the parameters of the two-exponential decay of the luminescence kinetics depend significantly on the size of the QDs: 1.8 and 26.8 ps correspond to QDs with a size of 2 nm; 4.5 and 68 ps correspond to QDs with a size of 2.9 nm. Based on a model from published data [5][6][7][8][9] obtained using incoherent photon echo spectroscopy [10][11][12], we suggested that the features of the detected luminescence kinetics can be explained as follows: an increase in the luminescence intensity is associated with the population of the bottom of the conduction band during electron termalization. We assume the existence of one type (Fig.…”

On the impact of the laser radiation wavelength and the concentration of quantum dots on the luminescence spectra of colloid solution and QD-doped nanocomposites

“…Excitation power and wavelength dependence measurements were carried out with the use of QDs on glass plate. This sample was prepared with the blade coating technique that was previously described in [9].…”

Incoherent exciton echo on the CdSe/CdS/ZnS semiconductor quantum dots

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The possibility and conditions of an incoherent exciton echo excitation in a thin layer of the CdSe/CdS/ZnS semiconductor quantum dots spread on a glass substrate are discussed.An experiment on the incoherent photon echo (IPE) in a thin layer of CdSe/CdS/ZnS semiconductor quantum dots (QDs) spread on a glass substrate was reported in [1][2][3]. The authors studied QDs manufactured by «QD-light» (Russia) using the colloidal synthesis technique.

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“…The experimental work [8] (and the monograph by Novotny and Hecht [9]) states that a photon excitation of semiconductor QDs necessarily leads to an excitation of Wannier-Mott excitons, whose size is approximately equal to the size of QDs. The question arises: was the excitation of Wannier-Mott excitons taken into account in [1][2][3] and was there an incoherent exciton echo (IEE) at localized excitons?Note that the excitation of laser pulses and the capture of optical responses is conveniently carried out using prisms of total internal reflection [10]. In the IPE mode, a noise optical pulse will first excite free electron-hole pairs [11], which then, losing energy, turn into coupled electron-hole pairs, i.e.…”

“…to Wannier-Mott excitons, which are the only form of a photon excitation in semiconductor QDs. Following [12], we assume that these excitons will be localized, and the experimentally observed response [1][2][3] is the IEE at local excitons.In Russia, the IPE technique was implemented by Yu.G. Vainer [4], who rightly asserted that the temporal resolution of the photon echo method is determined in the general case not by the duration of the exciting pulses Δt, but by the radiation coherence time τc, i.e.…”