Band gap and Schottky barrier heights of multiferroic BiFeO3

Abstract

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Photoconductivity and photo-detection response of multiferroic bismuth iron oxide

“…[4][5][6][7][8][9][10] The optical properties of BiFeO 3 (BFO) are also different from most of the perovskite ferroelectric due to its lower bandgap (2.6-2.9 eV) and conducting domain walls. 11,12 Clark and Robertson 13 predicted both direct and indirect bandgaps around 2.5 eV using band structure model, and afterward Ihlefeld et al 14 reported a direct-gap transition at 2.74 eV; however, recently we also found a direct bandgap of 2.55 eV at T ¼ 295 K, an indirect band edge at 2.67 eV. 5 Conventional photoelectric (PE) devices are based on two basic principles: first, the generation of electrical charge carriers in the active medium under the illumination of light; and second, separation and detection of photoinduced charge carriers by in-built asymmetric potential of p-n junction or Schottky junction or difference in work function between electrodes and semiconductor.…”

Screening effects in ferroelectric resistive switching of BiFeO3 thin films

“…42 Apart from other smaller corrections, 40 this value assumes non-polar BiFeO 3 and a clean metal-semiconductor interface, both conditions not being satisfied in our case: the bound surface charges associated to a polarization pointing down inside the ferroelectric domains are expected to increase the barrier height for electrons injected from the Cr electrode, as indeed observed. In addition, measurements in air allow for adsorbates to act as screening charges and they also contribute to changes in the electronic potential.…”

Phonon spectroscopy near phase transition temperatures in multiferroicBiFeO3epitaxial thin films

“…Whether the transition is a Mott transition or a band transition is unproven. Various theoretical models disagree: Vasquez et al [3] get an ab initio Mott transition; Clark et al [23] got a band transition to a semimetal from a screened exchange model.…”