Monitoring of V2+ and V3+ in vanadium-doped CdTe: a combined magnetic circular dichroism and electron paramagnetic resonance approach
Magnetic circular dichroism (MCD) is demonstrated to allow the simultaneous characterization of the V2+ and V3+ ions in vanadium-doped Bridgman grown CdTe bulk samples. The identification of the MCD bands relies on the analysis of n- and p-type co-doped samples as well as on spectroscopic arguments. A direct correlation of the strength of certain MCD bands with the V3+ concentrations determined by electron paramagnetic resonance spectroscopy allowed the calibration of our spectra for V3+. Based on photo-MCD experiments, we also provide a calibration of MCD bands related to V2+. Finally, the [V2+]/[V3+] ratio can be derived simply from the shape of the MCD spectrum in the low-energy region (E<1.1 eV).