Effects of Zn-doping on structure and electrical properties of p-type conductive CuCr1-x Zn (x) O-2 delafossite oxide

摘要

Delafossite-type CuCr1-x Zn (x) O-2 (x = 0, 0.03, 0.05, 0.07, 0.1) conductive oxides were synthesized by sol-gel method, and the effects of Zn-doping on morphology, structure, and electrical properties of the CuCr1-x Zn (x) O-2 oxides were investigated. Based on X-ray diffraction (XRD) and Raman spectrum, the crystalline quality of the oxides is improved by the suitable substitution of Cr by Zn. The X-ray photoelectron spectroscopy (XPS) spectra reveal the chemical state of Zn is +2. The Hall and Seebeck coefficients of the pellet samples display a positive sign, indicating p-type conductive characteristics of the obtained oxides. The temperature-dependent resistivity of the oxides is proven to be consistent with small polaron hopping. For the three oxide samples with x = 0, 0.05, and 0.1, the activation energies for the polaron hopping between Zn2+ and Cr3+ sites are 54, 41.5, 32 meV, respectively, which is found to decrease with the increase of Zn content. The electrical conductivity can be remarkably improved by Zn-doping due to the small polaron hopping activation energy. These properties render this material promising as transparent electrode in optoelectronic industry.