Cobalt acceptor state in silicon: Temperature dependence of the energy level and capture cross section

Abstract

We correlate results of optical-absorption, photoconductivity, resistivity, and Hall-effect measurements to show that the cobalt acceptor level is essentially fixed in energy 0.535 ± 0.013 eV below the conduction-band edge as the energy gap of silicon changes with temperature. Comparison of this result with measurements of the electron thermal emission rate leads to the first estimate of the temperature dependence of the cross section for capture of electrons by neutral cobalt acceptors, ${\sigma }_n^0\sim T^m$, with $m=-0.1\mathrm{}\pm 0.7$.