Structural, Electronic Structure, and Electrical Properties of Pure and Vanadium-Doped CuCrO2 Thin Films

Delafossite CuCrO2 (CCO), CuCr0.96V0.04O2 (CCVO) thin films were successfully prepared on Si (100) substrates, using the pulsed laser deposition technique. The effect of doping was studied using x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), temperature-dependent resistivity measurements, and I-V characteristics. The XRD results confirmed the single-phase rhombohedral structure of the prepared thin films, and the XAS results conveyed the mixed Cu+ and Cu2+ ions in the CCVO and CCO samples. The valence state of Cr was unaltered under the doping effects and remained + 3 (i.e., Cr+3). The modified hybridization of the O 2p orbitals with the metal d (V, Cr,) orbitals was confirmed in the O K-edge spectra. Insertion of V5+ ions in the CCO lattice introduced an electron doping effect. Thus, the basic p-type character of CCO was affected by the V doping and, therefore, increases in the resistivity or decreases in the p-type character were observed in the I-V measurements. From this study; the method of selective mono-doping can be a useful tool to tailor the bandgap and the type of conductivity in other delafossite semiconductors.