Electric field dependence of the exciton binding energy in GaAs/${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As quantum wells

Exciton binding energies in GaAs/${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As quantum wells are calculated as a function of the external electric field applied perpendicular to the heterointerface, using the equations which are free from errors in the paper of D. A. B. Miller et al. [Phys. Rev. B 32, 1043 (1985)]. The calculated results agree well with other more elaborate calculations.