  In this study, we have investigated the photoionization cross section of an
on-center hydrogenic impurity in a multi-layered spherical quantum dot. The
electronic energy levels and their wave functions have been determined fully
numerically by shooting method. Also, we have calculated the binding energy of
the impurity by using these energy values. The photoionization cross section
has also been computed as a function of the layer thickness and normalized
photon energies. We have discussed in detail the possible physical reasons
behind the changes in the binding energies and photoionization cross section.
It is observed that both the binding energies and the photoionization cross
sections depend strongly on the layer thickness and photon energies.
