Exciton and Bi-exciton Binding Energy Calculation in a Core Shell Quantum Dot

Abstract

We report the effect of shell thickness on exciton and biexciton binding energy calculation for a CdSe/ZnSe core shell quantum dot. Wentzel Kramers Brillouin approximation help us to create proper wave function for the system. It incorporates core shell boundary effect correctly. For excitons, the binding energy is affected by the Columbic confinement potentials and during biexciton binding energy calculation, the exchange and correlation effects were taken into account. It is observed that the excitonic binding energy shows an initial increase with increasing shell thickness but saturates for thick shell while it always gives a negative value for bi-excitonic binding energy. This confirms the existence of antibonding states for biexcitons.