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

Abstract

Delafossite CuCrO₂ (CCO), CuCr_0.96V_0.04O₂ (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.