Low-energy exciton states in a nanoscopic semiconducting ring

We consider an effective mass model for an electron-hole pair in a simplified confinement potential, which is applicable to both a nanoscopic self-assembled semiconducting InAs ring and a quantum dot. The linear optical susceptibility, proportional to the absorption intensity of near-infrared transmission, is calculated as a function of the ring radius R-0. Compared with the properties of the quantum dot corresponding to the model with a very small radius R-0, our results are in qualitative agreement with the recent experimental measurements by Pettersson et al.