Electrical field effect on the optical threshold energy of donor and acceptor levels in chromium-doped GaP

Abstract

The electrical field effect on the optical threshold energy have been studied using electrical deep level optical spectroscopy technique. The measurements were focused on the Cr 3+/4+ donor level and on the Cr 2+/3+ acceptor level in Cr-doped GaP. It is found, in the case of the Cr 3+/4+, that the optical threshold as the thermal ionization energies are field dependent. This behavior allows us to determine each position at zero field and then the Frank–Condon shift. Using these parameters, a configuration coordinate diagram is given. In the case of the Cr 2+/3+ acceptor level, the optical threshold is also field dependent.