Crystal growth and electrical properties of CuFeO2 single crystals

Delafossite-type CuFeO2 single crystals have been prepared by a flux method: crystals obtained in a Cu crucible with LiBO2 as flux are n-type whereas those prepared in a Pt crucible with a Cu2O flux are p-type. Electrical measurements have revealed that n-type crystals exhibit weak anisotropic conductivities with large activation energies and small mobilities (r.t. values perpendicular and parallel to the c-axis: μ⊥ = 5 × 10−5 and μ‖ = 10−7 cm−2 V−1 sec−1). p-type crystals, less anisotropic, are characterized by low activation energies and higher mobilities (μ⊥ = 34 and μ‖ = 8.9 cm2 V−1 sec−1). A two -conduction-band model is proposed to account for the difference observed between the energy gap value deduced from photoelectrochemical measurements and the activation energy of the electrical conductivity in the intrinsic domain.