The Spectrum of Natural Frequencies of Acoustic Oscillations of a Spherical Quantum Dot with a Multilayer Shell

Authors R. Peleshchak1,2, O. Kuzyk1, О. Dan′kiv1

1Ivan Franko Drohobych State Pedagogical University, 24, Ivan Franko St., 82100 Drohobych, Ukraine

2Lviv Polytechnic National University, 12, Stepan Bandera St., 79013 Lviv, Ukraine

Issue Volume 13, Year 2021, Number 4
Dates Received 02 July 2021; revised manuscript received 04 August 2021; published online 20 August 2021
Citation R. Peleshchak, O. Kuzyk, О. Dan′kiv, J. Nano- Electron. Phys. 13 No 4, 04031 (2021)
PACS Number(s) 43.35. + d, 62.23.Eg
Keywords Core/shell quantum dot, Acoustic wave (3) , Frequency of acoustic oscillations, Deformation (8) .

A model that allows to determine the spectrum of acoustic oscillations of a spherical quantum dot (QD) of the core/multilayer shell type within the elastic continuum has been developed. The proposed model takes into account the dependence of elastic constants (acoustic wave velocities) on the geometric dimensions of the core of a QD and individual layers of its shell. Within the framework of the developed model, the spectrum of acoustic oscillations for QDs of the type of the InAs core with a single-layer GaAs shell and a double-layer GaAs/In0.4Ga0.6As shell is calculated. It is established that the presence of a shell in a QD leads to a significant decrease in the natural frequencies of acoustic oscillations. It is shown that an increase in the number of shell nanolayers leads to a decrease in the degree of correlation between the frequencies of acoustic oscillations and the radius of the QD core. This is explained by the fact that frequencies of oscillations are mainly determined by two competing factors: the dependence of the frequency of oscillations on the QD radius and the dependence of the propagation velocities of longitudinal and transverse oscillations in thin layers on their thicknesses. The first factor contributes to a decrease in the frequency with increasing QD radius, and the second factor contributes to a decrease in the frequency with a decrease in the number of atoms in nanolayers (a decrease in their thickness).

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