Photoionization cross section of hydrogenic impurities in cylindrical quantum wires: Infinite well model

We have used a variational wave function for hydrogenic impurities in cylindrical quantum wires to calculate the dependence of the photoionization cross section of such impurities on the photon energy. The calculation has been performed using the infinite well model. The transition takes place between the impurity level associated with the ground subband and the free particle state in the free excited state for hydrogenic impurities at the center of a cylindrical quantum wire. The result is presented for various wire radii at the center of a cylindrical quantum wire. We see that the peak value initially increases with increasing wire size, reaching a maximum value and then decreasing with a further increase in wire size, because the binding energy increases with decreasing wire radius. This peak value occurs when the photon energy is larger than the difference between the final and initial state energies of the impurity.