Structural, morphological and optical properties of BiFe0.99Cr0.01O3 thin films

Ameer, Shaan; Jindal, Kajal; Sharma, Savita; Jha, Pradip K.; Tomar, Monika; Gupta, Vinay

doi:10.1016/j.vacuum.2018.09.051

Cited by 9 publications

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“…The absorption spectrum of the BFO film annealed at 550 °C has a wider absorption range in the visible region. In order to evaluate the optical band gaps of the BFO films, the absorption spectra are fitting based on the Tauc formula [31]: (αhν)2=A(hv−Eg) where hν is the photon energy, A is a constant, α is the absorption coefficient and E g is the optical band gap. Figure 6b shows plots of ( αhν ) 2 and hν for the samples.…”

Section: Resultsmentioning

confidence: 99%

“…The enhancement of photovoltaic effect in 550 °C annealed BFO film is due to two reasons. On the one hand, reduced band gap and an increased absorption coefficient allow the film to absorb more photons, on the other hand, the larger polarization could separate the electron and holes more effectively [31]. In this manner, the photovoltaic effect is enhanced.…”

Section: Resultsmentioning

confidence: 99%

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The Microstructure, Electric, Optical and Photovoltaic Properties of BiFeO3 Thin Films Prepared by Low Temperature Sol–Gel Method

et al. 2019

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Ferroelectrics have recently attracted attention as a candidate class of materials for use in photovoltaic devices due to their abnormal photovoltaic effect. However, the current reported efficiency is still low. Hence, it is urgent to develop narrow-band gap ferroelectric materials with strong ferroelectricity by low-temperature synthesis. In this paper, the perovskite bismuth ferrite BiFeO3 (BFO) thin films were fabricated on SnO2: F (FTO) substrates by the sol–gel method and they were rapidly annealed at 450, 500 and 550 °C, respectively. The microstructure and the chemical state’s evolution with annealing temperature were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), and the relationship between the microstructure and electric, optical and photovoltaic properties were studied. The XRD, SEM and Raman results show that a pure phase BFO film with good crystallinity is obtained at a low annealing temperature of 450 °C. As the annealing temperature increases, the film becomes more uniform and has an improved crystallinity. The XPS results show that the Fe3+/Fe2+ ratio increases and the ratio of oxygen vacancies/lattice oxygen decreases with increasing annealing temperature, which results in the leakage current gradually being reduced. The band gap is reduced from 2.68 to 2.51 eV due to better crystallinity. An enhanced photovoltaic effect is observed in a 550 °C annealed BFO film with a short circuit current of 4.58 mA/cm2 and an open circuit voltage of 0.15 V, respectively.

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