A theoretical and experimental formalism of electronic structure of BFO:Cr thin films and modulation of their electrical properties upon visible light illumination

Abstract

BiFeO3 (BFO) and BiFe1-xCrxO3 (BFCO) (x = 0, 0.01, 0.02, 0.03) thin films have been fabricated using chemical solution deposition technique. The bandgap of BFO and BFCO thin films is found to be lying in the visible region making these films suitable candidates for potential solar energy harvesting applications. Density functional theory based calculations have also been performed to study the effect of B-site (Cr) doping on the electronic properties of BFO and BFCO. The BiFe1-xCrxO3 (x = 0.02) thin films exhibited well saturated PE hysteresis loops with a maximum remanent and saturation polarization of about 43 μC/cm2 and 64 μC/cm2, respectively. In contrast to pure BFO, a high value of short circuit current density (Jsc) of magnitude 766.60 μA/cm2 along with the open circuit voltage (Voc) of 106 mV was obtained for BiFe0.98Cr0.02O3 thin film structure under illumination with a laser of wavelength 470 nm and intensity 20 mW/cm2. The Au/BiFe0.98Cr0.02O3/ITO/glass heterostructure displays a remarkably enhanced value of Ion/Ioff ratio (8.4 × 104). The observed results clearly highlight the potential of Cr doped BFO thin film structure for the development of cost effective light-driven devices.

Theoretical insight of origin of Rashba–Dresselhaus effect in tetragonal and rhombohedral phases of BiFeO3

“…35 The generalized gradient approximation (GGA) with the PBE functional was used to describe the exchange correlation energy. 26 A Hubbard parameter ( U ) of 5 eV was used to treat the on-site Coulomb interaction for the Fe 3d states. 36 A plane wave cut-off energy of 400 eV and energy convergence criterion of 1 × 10 −6 eV were used for self-consistent calculations.…”

“…[23][24][25] Ferroelectric transition metal oxides are well known for their potential applications in the field of photovoltaics, memory devices, and tunable capacitors due to their unique structural, electrical and magnetic properties. 26 Therefore, the present work aims at finding the Rashba parameter for a multiferroic system, BiFeO 3 (BFO), which is a noncentrosymmetric transition metal oxide. It possesses both ferroelectricity and G-type antiferromagnetism at room temperature, as its Curie and Ne ´el temperatures are 1103 K and 643 K, respectively.…”