Biexciton Binding Energy in Spherical Quantum Dots with Γ8 Valence Band

Abstract

The biexciton binding energy in spherical CdSe/ZnSe quantum dots is calculated variationally in the framework of kp-perturbation theory. Smooth and abrupt confining potentials with the same localization area of carriers are compared for two limiting cases of light hole to heavy hole mass ratio β = m_lh/m_hh: β = 1 and β = 0. Accounting for correlations between carriers results in their polarized configuration and significantly increases the biexciton binding energy in comparison with the first order perturbation theory. For β = 0 in smooth confining potentials there are three nearby biexciton states separated by small energy gap between 1S_3/2 and 1P_3/2 hole states.