Effect of shell thickness on exciton and biexciton binding energy of a ZnSe/ZnS core/shell quantum dot

TL;DR

This study investigates how varying shell thickness in ZnSe/ZnS core/shell quantum dots affects exciton and biexciton binding energies, revealing non-monotonic behavior and antibonding states at larger thicknesses.

Contribution

It provides a theoretical analysis of shell thickness effects on exciton and biexciton energies using the WKB approximation, highlighting non-linear trends.

Findings

Exciton binding energy increases with small shell thickness

At larger shell thickness, exciton binding energy decreases

Biexciton states become antibonding at thicker shells

Abstract

The exciton and biexciton binding energy have been studied for a ZnSe/ZnS core/shell quantum dot using WKB (Wentzel-Kramers-Brillouin) approximation. The exciton binding energy increases for small shell thickness and for large thickness, the binding energy again starts decreasing. A similar result is obtained for biexcitons where for thicker shells, the biexciton attains antibonding.