Elastic Versus Inelastic Energy Loss of Recoil Germanium and Silicon Atoms

Experiments of Wikner and van Lint have established the photoneutron method of producing displacement radiation effects by measuring the effect of recoils from $\mathrm{Si}(\gamma , n)$ reactions on the excess carrier lifetime. These experiments have been extended to Ge together with an additional experiment in which Si and Ge were bombarded by a 1-MeV reactor neutron spectrum and a mono-energetic beam of 14-MeV neutrons. The range of average energies of the recoil atoms from the bremsstrahlung experiment spans the range of the recoil atom energies of the neutron experiment, so that the results can be compared with theoretical calculations which assume varying percentages of elastic and inelastic energy loss of the recoils. The results are in good agreement with the theory given by Lindhard et al., which is based on a broad transition-energy region between elastic and inelastic energy losses.