Conduction mechanism in mesoporous hematite thin films using low temperature electrical measurements and theoretical electronic band structure calculations

摘要

Low temperature four-probe electrical resistivity and magnetoresistivity measurements in mesoporous hematite thin films imply that the operative conduction mechanism involves impurity band with intrinsic donor defects. The surface morphology revealed the porous nanostructures with necked particle size ranging from 17 nm to 23 nm. Due to the presence of ionized and high magnetic spin configuration of Fe 3d-electrons states in alpha-Fe2O3, it shows spin magnetic moment per ion 4.17 mu B as described by a Hubbard-type on-site Coulomb repulsion (GGA+U approach), which was found to provide an accurate description of the electronic properties which is good agreement with reported results. It has an estimated band gap about 2.2 eV with enhanced photocurrent (16.73%) properties and could promise photoelectrochemical applications. (C) 2016 Elsevier B.V. All rights reserved.