Enhanced Photocurrent in Rh-Substituted $\alpha$-Fe$_{2}$O$_{3}$ Thin Films Grown by Pulsed Laser Deposition

Abstract

Rh-substituted α-Fe2O3 (Fe2-xRhxO3; 0.0≤x≤2.0) thin films were grown on α-Al2O3(110) substrates with a Ta-doped SnO2 electrode layer by pulsed laser deposition. Highly oriented epitaxial films with pure corundum structures were successfully fabricated over the entire compositional range. The optical absorption spectra of the films indicate narrowing of the bandgap with increasing Rh content. Consequently, the photoelectrochemical performance was improved in the Rh-substituted films. We found that the optimum Rh content lies at around x=0.2, where the photocurrent is significantly enhanced over a wavelength range of 340–850 nm.