THE EFFECT OF THE ELECTRIC-FIELD ON THE PHOTOIONIZATION CROSS-SECTION

The effect of the electric field on the donor impurity is investigated in the case of a spherical conduction band with the use of a variatio nal procedure. An analytical expression for the photoionization cross- section as a function of photon energy within the effective mass appro ximation of an impurity atom in an applied field was obtained. The eff ect of central cell correction by means of a semiempirical short-range potential is taken into account. It has been found that the binding e nergy and the spectral dependence of the cross-section are very sensit ive to the electric field, the shape of the impurity potential and the ir combined effect.