An effective-mass equation for the hole binding energy of an acceptorlike bound exciton in semiconductors is developed. The motion of the electron is represented by an effective charge which modifies the Coulomb interaction. An expression for the oscillator strength of the bound exciton is given in terms of the wave function of the bound-exciton state. The theory is applied to the GaP:N system, which gives hole binding energies for excitons bound to nitrogen pairs in good agreement with experiment, and predicts that the electron binding energy for an isolated-nitrogen-bound exciton is about 6 meV.

• Received 6 December 1991

DOI:https://doi.org/10.1103/PhysRevB.45.9025