Electron paramagnetic resonance and an optical investigation of photorefractive vanadium-doped CdTe

Electron paramagnetic resonance (EPR), photo-EPR, optical absorption, and photoluminescence measurements have been made on photorefractive vanadium-doped CdTe. This EPR observation of the ${\mathrm{V}}^{3+}$ ion in CdTe, along with the observed features assigned to ${\mathrm{V}}^{2+}$ in the optical-absorption spectrum, provide direct evidence for the substitutional incorporation of vanadium. Photo-EPR measurements were also conducted and provide direct evidence for the optical activity of ${\mathrm{V}}^{3+}$ under sub-band-gap illumination. A qualitative discussion linking these observations to photoionization channels is presented.