Abstract: The relation between the exciton binding energy and the spherical quantum dot radius  has been calculated using the variational method.Calculations were performed using both the infinite and finite confining potential well model.The results show that the exciton binding energy decreases as the dot radius increases for infinite confining well model.For the finite confining well model,the binding energy reaches a peak value as the dot radius increases and then decreases to a limiting value corresponding to that in the barrier material.These results are important for the study of the physical properties of exciton in quantum dot.

Key words: variational approach, quantum dots, exciton, binding energy, wave function