Band gap determination in multi-band-gap CuFeO<sub>2</sub> delafossite epitaxial thin film by photoconductivity

Abstract
The photoconductivity within a wavelength range of 450-1100 nm was determined for a sample of epitaxial delafossite CuFeO2 film grown by pulsed laser deposition. The film thickness was estimated to be 75 nm. The resistance of the films was determined with four-contact van der Pauw's method and using monochromatic illumination of the film. The most significant change in resistance resulted in three rapid lineal conductivity increases at photon energies of similar to 1.5 eV (gap-1), similar to 2.1 eV (gap-2) and similar to 2.5 eV (gap-3). The conductivity properties are well correlated with prior optical absorption results obtained in the NIR-VIS region using transmittance spectroscopy.
Description
Keywords
Semiconductor band-gap, Photoconductivity, Water photolysis, Thin film, Solar spectrum, Monochromatic light
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