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 ratioσ^(c),such that ifσ>σ^(c)(σ<σ^(c))the X^(+)configuration is stable(unstable),andσc increases as the strength of the confinement increases.