Electronic and Level Statistics Properties of Si/SiO2 Quantum Dots

TL;DR

This paper models the electronic and statistical properties of Si/SiO2 quantum dots, analyzing energy levels, exciton recombination, and confinement regimes to understand their optical and electronic behavior.

Contribution

It introduces a comprehensive model for Si quantum dots considering nonparabolicity and calculates energy levels, exciton energies, and statistical distributions, advancing understanding of their quantum properties.

Findings

Strong confinement regime for D<6nm with few energy levels.

Reproduction of PL exciton data by the model.

Statistical distribution of electron energy levels for D>10nm.

Abstract

Spherical shaped Si quantum dots (QDs) embedded into the SiO2 substrate are considered in the single sub-band effective mass approach. Nonparabolicity of the Si conduction band is described by the energy dependence of electron effective mass. Calculations of low-lying single electron and hole energy levels are performed. For small sizes QD (diameter D<6nm) there is a strong confinement regime when the number of energy levels is restricted to several levels. The first order of the perturbation theory is used to calculate neutral exciton recombination energy taking into account the Coulomb force between electron and heavy hole. The PL exciton data are reproduced well by our model calculations. For weak confinement regime (size D>10 nm), when the number of confinement levels is limited by several hundred, we considered the statistical properties of the electron confinement. Distribution function for the electron energy levels is calculated and results are discussed.