A Bound State of a Positively Charged Exciton in Quantum Dots

Using the method of few-body physics, we obtain the relation between the correlation energies of the low-lying states of the positively charged exciton X⁺ and the radius of quantum dots. We also calculate the binding energies of the ground state of a positively charged exciton as a function of the electron-to-hole mass ratio for a few values of the strength of the confinement. We find that there exists a critical mass ratio σ^c, such that if σ > σ^c (σ < σ^c) the X⁺ configuration is stable (unstable), and σ^c increases as the strength of the confinement increases.