Electrical field effect on both thermal ionization energy and optical threshold energy of the Cr3+/4+ deep donor level in GaP

The effect of the electric field on both thermal ionization energy and optical threshold energy have been studied using deep level transient spectroscopy (DLTS) and electrical deep level optical spectroscopy (Electrical DLOS) techniques in Cr-doped GaP. The measurements were focused on the Cr3+/ 4+ donor level. It is found that the ionization energy Ei decreases with the electrical field F as in the case of the Poole–Frenkel model. It is found that there is a variation of the optical threshold with the electrical field.