Dimensional effects on exciton states in nanorings

Exciton states in nanorings are studied within the framework of the effective-mass approximation. The exciton level structure and binding energy in one- and two-dimensional nanorings are found to be very different at small and large radius limits. The variation of exciton energy levels with radius and width is shown. The important role of Coulomb interaction in exciton spectra is revealed. Our study is helpful for understanding the transition of exciton states from the one-dimensional case to the two-dimensional case