Andrey V. Amosov

Biexciton in nanoheterostructures of dielectric quantum dots

Abstract. It has been found that the formation of a biexciton in a nanoheterostructures (NHS) made up of aluminum oxide quantum dots (QDs) synthesized in a dielectric matrix is of threshold character and can occur in a nanosystem, where the distance D between the surfaces of QD is given by the condition Dc(1)≤D≤Dc(2). We have shown that with such an NHS acting as “exciton molecules” (biexcitons consisting of spatially separated electrons and holes) are the QDs of aluminum oxide with excitons localizing over their surfaces. The position of the biexciton state energy band depends both on the mean radius of the QDs, and the distance between their surfaces, which enables one to purposefully control it by varying these parameters of the nanostructure.

Exciton photoluminescence of SiO2 nanoparticle powder

The paper reports the study of photoluminescence (PL) of disc- and elliptical-shaped SiO2 nanoparticles exited by photons with energy lower than silica bandgap. Differences in the PL spectra are found to be associated with the structure of the nanoparticle excitonic states of optical electrons.

Excitons and low-threshold optical nonlinearity of dielectric nanosystems

The recently discovered ultralow-threshold nonlinear refraction of low-intensity laser radiation in dielectric nanostructures has an atypical dependence on radiation intensity. We first carry out quantitative measurements of the dependence of the nonlinear response of liquid dielectric nanostructures on the low-intensity radiation and then devise a theoretical explanation. The theory suggests that the nonlinearity is of photoinduced nature instead of a thermal one and depends directly on the nanoparticles electronic structure and the relationship between permittivities of dielectric matrix and nanoparticles.

Optical absorption by excitons of quasi-zero dielectric quantum dot

As a part of the dipole approximation we study the interband optical absorption by nanosystem containing quantum dots (QD) alumina in a dielectric matrix. It is shown that the absorption edge of nanosystem mainly formed by two comparable in intensity electron transitions from low excited size quantized hole states on the ground size quantized electron state.