A possible model: Photothermal excitation via an excited state in the Si:Pd level

Abstract

The electron photoionization cross-section spectra of the Si:Pd EA level at various temperatures are obtained for the first time. It is shown that the cross-section spectra around the threshold energy shift to lower energy when the temperature rises. Instead of the variation of the energy gap or the broadening effect of lattice relaxation, photothermal excitation via an excited state at 45 meV below the bottom of the conduction band causes this energy shift. The energy from the ground state to the excited state derived from both optical and thermal data is 370 meV.