Fermi level scan spectroscopy of gap states in Ge and Si-Ge alloys based on the kinetics of neutron transmutation doping

A study of the kinetics of neutron transmutation doping of Ge served as a basis for a number of methods that yielded the exact values of some nuclear parameters of Ge isotopes, precisely characterized the neutron-transmutation-doped Ge, and made it possible to create the so-called “Fermi level scan spectroscopy” for analysis of deep-level electronic states in the energy gap. The development of this technique is reported and illustrated by application to the long-standing problem of double Se donor states in Ge. Possible applications of the method to the states in the energy gap of “dirty” Ge and Si-Ge alloys are considered as well.