Nanoscale physics

Baric properties of quantum dots of the type of core (CdSe) – multilayer shell (ZnS/CdS/ZnS)
Kuzyk O.V.1, Dan’kiv O.O.1, Peleshchak R.M.1,2, Stolyarchuk I.D.1
1 Drohobych Ivan Franko State Pedagogical University, 24, Ivan Franko Str.,  Drohobych,  Ukraine. 
E-mail: olehkuzyk74@gmail.com
2 Lviv Polytechnic National University, 12, Stepan Bandera Str., Lviv, Ukraine.

Surface passivation of QD due to the use of shell of different materials, proved to be an effective approach to reduce surface defects, which can expand the spectrum of absorption, accelerate the transfer of current carriers and reduce recombination losses. A special positive effect can be achieved if you use the multilayer shell. The QDs are sensitive to deformation, so they are used as sensors of mechanical stress, to study and control the physical characteristics of nanomaterials [1]. The influence of pressure on the physical properties of QD is also related to surface conditions (type of shell, its thickness and number of layers). Additional pressure can be created by adsorbed atoms on the surface of the QD (for example, when interacting with drugs), impurities that alloy the QD, or an acoustic wave. In this work, we construct the model of spherical QD of the type of core (CdSe) – multilayer shell (ZnS/CdS/ZnS), which undergoes comprehensive pressure, taking into account the mismatch of the lattice parameters of the contacting layers and the pressure due to the curvature of the surface.
External pressure leads to shift the edges of the allowed bands, thereby changing the energy spectrum of electrons and holes and the width of the band gap [2]. Under certain conditions (when the hydrostatic pressure exceeds some critical value), the value of the baric coefficient changes (the nonlinear dependence of the radiation energy of QD on the value of the pressure appears).

1.  Fan H., Ni Z., Feng Y, Fan. X, Kuo Z. High pressure photoluminescence and Raman investigations of CdSe/ZnS core/shell quantum dots // Appl Phys Lett.-2007.-90.-P. 021921.
2.  Peleshchak R., Kuzyk O., Dan’kiv O. The influence of the electrically inactive impurity on the energy spectrum of electron and hole in InAs/GaAs heterostructure with InAs quantum dots // Rom J Phys.-2020.-65.-P. 610.