Partially confined excitons in semiconductor nanocrystals with a finite size dielectric interface

TL;DR

This paper investigates how finite potential barriers and dielectric mismatch influence excitonic properties in semiconductor nanocrystals, proposing a realistic dielectric interface model that affects exciton binding energies.

Contribution

It introduces a finite size smooth dielectric interface model to accurately study excitonic effects, avoiding unphysical divergences in self-polarization energy.

Findings

Excitonic binding energy varies significantly with dielectric interface thickness.

Binding energy can surpass infinite barrier confinement or be nearly zero depending on parameters.

The model provides a more realistic description of dielectric effects in quantum dots.

Abstract

The combined effect of finite potential barriers and dielectric mismatch between dot and matrix on excitonic properties of semiconductor quantum dots has been studied. To avoid the unphysical divergence in the self-polarization energy which arises for the simplest and profusely adopted step-like model of the dielectric interface, we proposed a realistic (finite size) smooth profile for the dielectric interface. We have found that the excitonic binding energy can be either higher than the corresponding one to complete confinement by infinite barriers or essentially zero for a wide range of dot sizes depending on the thickness of the dielectric interface.