Influence of divalent Ni and trivalent Cr ions on the properties of ytterbium modified bismuth ferrite

Impact of (Zr, Cu) Ion Substitution on the Optical, Dielectric, and Impedance Behavior of BiFeO3

“….0 eV [40]. It was found that Yb-and Co-co-doped BFO exhibited an optical bandgap (1.5 eV) lower than that of undoped BFO (2.15 eV) [21].…”

“…It was found that Yb-and Co-co-doped BFO exhibited an optical bandgap (1.5 eV) lower than that of undoped BFO (2.15 eV) [21]. Vanga et al [40] have demonstrated that the bandgap of Ni-, Cr-doped BFO decreases with the concentration of Ni/Cr. They have obtained a bandgap of 1.99 eV.…”

“…'n' value depends on the nature of electronic transition which causes absorption. For direct bandgap transition, n = 2 and for the indirect bandgap, n = ½ for direct bandgap [40]. Considering BFO as a direct bandgap material, the bandgaps are calculated taking n = ½.…”

“…It has been demonstrated that co-substitution of Gd and Mn in BFO resulted in reduced bandgap energy [10]. Vanga et al [14,40] have reported decreased bandgap for Ni, Cr and Nd, Ni codoped BFO nanoparticles. Furthermore, Sm and Ni co-doping of BFO also introduced a decrease in bandgap compared with undoped BFO [42].…”

“…Reported values for the optical bandgap of BiFeO 3 at room temperature range from 1.7 to 2.8 eV [10,21,[31][32][33][34][35][36][37][38][39]. According to many authors, BFO is a direct bandgap semiconductor [14,34,35,40], while few others have calculated both the direct and indirect bandgaps [32,33,37,41]. Extensive investigations have been carried out to tune the optical bandgap of BFO ceramic by introducing this co-doping approach.…”