Structure, composition and properties of p-type CuCrO2 thin films

In this study, correlations between composition, structural and optoelectronic properties of the p-type CuCrO2 film are discussed. The film crystal structures can be altered from composite to single phase by adjusting the Cu, Cr and O contents. The appropriate composition is a dominant factor for the formation of pure phase CuCrO2, and the content discrepancy between the Cu and Cr should be equal to, or lower than, 2.6 at% in the material. A higher stoichiometric ratio of oxygen is necessary to stabilize the structure of delafossite and is responsible for p-type electrical conductivity. CuCrO2 has a continuously bonded polygonal microstructure. Intrinsic CuCrO2 is a transparent wide band gap semiconductor, in which the transmittance is 68% at visible wavelength of 550 nm. Higher incident photon energy can cause subband transition in CuCrO2. The direct band gap of the CuCrO2 film is 3.17 eV, and with lower resistivity of 2.35 Omega cm. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.