Investigation of structural, morphological, optical, and electrical properties of CuCrO2 films prepared by sol–gel method

Abstract

High-quality p-type CuCrO2 thin films have been deposited on (001) sapphire substrates by the sol–gel method which is low cost, easy setup, large area coating, and mass production. The sol–gel derived films were pretreated at 400 °C for 20 min in air and then annealed at 600–1000 °C for 1 h in flowing nitrogen gas (N2). The influence of annealing temperature on the structural and optoelectronic properties of CuCrO2 thin films was systematically investigated. The microstructure, surface morphology, optical, and electrical properties of the films was characterized by XRD, FE-SEM, UV–Vis spectrometer, and Hall effect measurement. It shows that single-phase delafossite–CuCrO2 films were all highly c-axis oriented; the surfaces were smooth and consist of fine particles, whose grain sizes change with annealing temperatures. The maximal transmittance of CuCrO2 films can reach 90 % in the visible region with the optical band gaps ranging between 3.15 and 3.2 eV. The lowest resistivity was obtained with annealing at 800 °C, and a resistivity of 92.85 Ω cm was achieved at room temperature. The results suggest that the temperature in the annealing process plays a primary role in the formation of delafossite–CuCrO2 thin films. High-quality p-type CuCrO2 thin films have been deposited on (001) sapphire substrates by the sol–gel method annealed at 600–1000 °C for 1 h in flowing nitrogen gas (N2). The optimum values obtained for CuCrO2 film with the thickness of ~142 nm were ρ = 92.85 Ω cm and T = 90 %, indicating that CuCrO2 film may be a candidate for transparent applications.