Relation between the charge state of the Cr dopant in beta-Ga2O3 and the pinning of the Fermi level induced by deep traps created by either

The aim of this project is to study the relation between the pinning of the Fermi level induced by deep traps created by irradiation (with either protons or X-rays) and the charge state of the Cr dopant in β-Ga2O3. Since the luminescence of Cr3+ is characterized by two narrow emission lines superimposed on a broad band, fast XANES coupled with luminescence measurements will quantify both the oxidation state of Cr and its luminescence as a function of X-ray irradiation damage. This shall help to better understand the influence of the Fermi level on the relative concentration of the different oxidation states of Cr and the role of the deep traps introduced by either X-ray or proton irradiation on the luminescence intensity of the Cr intraionic transitions. EXAFS analysis will indicate whether X-ray radiation promotes the same kind of defects as proton irradiation involved on the energy and charge transfer processes between β-Ga2O3 and Cr as well as in the Cr local environment.