Substrate influence on the optical and structural properties of pulsed laser deposited BiFeO3 epitaxial films

Himcinschi, Cameliu; Vrejoiu, Ionela; Friedrich, M.; Nikulina, Elizaveta; Ding, Li; Cobet, Christoph; Esser, N.; Alexe, Marin; Rafaja, David; Zahn, Dietrich R. T.

doi:10.1063/1.3437059

Cited by 62 publications

(46 citation statements)

References 30 publications

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“…The band gap was obtained from the extrapolation of αE 2 to zero leading a value of 2.71 ±0.04 eV, see figure 5b. The refractive index and extinction coefficient as well as the band gap are in goodagreement with the previously published data of BFO thin films [71][72][73]. Further manipulation of the band gap to lower values by chemical doping (feasible by ALD), should open interesting avenues for photovoltaic applications of these oxide perovskites 6,74.…”

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confidence: 81%

Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition

et al. 2015

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In this work, ferroelectricity is identified in nanocrystalline BiFeO3 (BFO) thin films prepared by low-temperature atomic layer deposition. A combination of X-ray diffraction, reflection high energy electron diffraction, and scanning transmission electron microscopy analysis indicates that the as-deposited films (250 °C) consist of BFO nanocrystals embedded in an amorphous matrix. Postannealing at 650 °C for 60 min converts the sample to a crystalline film on a SrTiO3 substrate. Piezoelectric force microscopy demonstrates the existence of ferroelectricity in both as-deposited and postannealed films. The ferroelectric behavior in the as-deposited stage is attributed to the presence of nanocrystals. Finally, a band gap of 2.7 eV was measured by spectroscopic ellipsometry. This study opens broad possibilities toward ferroelectric oxides on 3D substrates and also for the development of new ferroelectric perovskites prepared at low temperature.

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confidence: 81%

Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition

et al. 2015

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“…A similar procedure was also used for the characterization of the BiFeO 3 epitaxial thin films. 31,32 The fits are shown in Fig. 1(a) by continuous lines.…”

Section: Resultsmentioning

confidence: 98%

Raman spectra and dielectric function of BiCrO3: Experimental and first-principles studies

Himcinschi

Vrejoiu

Weißbach

et al. 2011

Journal of Applied Physics

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We present the complex dielectric function of BiCrO3 thin films in the energy range of 0.73–9.8 eV determined using spectroscopic ellipsometry. By analyzing the absorption onset region, it is shown that the optical bandgap of BiCrO3 is indirect, with a value of 2.27 eV. The imaginary part of the BiCrO3 dielectric function, ɛ2, calculated using density functional theory in the generalized gradient approximation with an Hubbard potential of 3 eV agrees well with the experimentally determined one. Raman spectra of both polycrystalline and epitaxial thin films of BiCrO3 are reported. The temperature dependent Raman measurements indicate a structural phase transition at ∼400 K which was confirmed also by x-ray diffraction investigations.

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“…The film with larger compressive strain of 0.84% shows about 40% lower than that of the film with smaller compressive strain of 0.19%. This result may be explained by the enlargement of the BFO band gap as reported by Himcinschi [26] and this energy shift results in reduced photo-exciting efficiency at fixed illumination energy and causes smaller . There are causes which account for PV properties that are considered minor but are mentioned as follows: 1) the interface roughness: different bottom electrodes after different pretreatments have controlled surface roughness below 1 nm, the influence from which should be constant; 2) a slight difference in work function [27] of bottom electrodes Pt (5.3 eV) and -FePt (5.0 eV) [28]; 3) the formation of the secondary phase Bi O ; and variation in surface morphology.…”

Section: Methodsmentioning

confidence: 85%

Photovoltaic Property of Multiferroic ${\hbox{BiFeO}}_3$ Films With Different Textures on Glass Substrates

Chang

Yuan²,

Chen

et al. 2014

IEEE Trans. Magn.

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The photovoltaic (PV) property of multiferroic BiFeO (BFO) nanocrystalline films with different textures on glass substrates has been studied. Highly textured BFO(001) films were obtained on ferromagnetic -FePt(001) bottom electrodes by sputtering, while the isotropic polycrystalline BFO films were prepared on 20-nm-thick Pt(111) bottom electrodes by pulse laser deposition. All studied BFO films exhibited significant PV effect under laser illumination with wavelength of 405 nm, and the short-circuit photocurrent density was increased with the increase of laser intensity. Large photocurrent density ( ) of A cm at laser power of mW cm was obtained in the BFO(001) film grown on 20-nm-thick FePt electrode, and the value was larger than that of the isotropic single phase BFO film by a factor more than 1.7. This difference could be explained by the depolarization effect along different lattice orientations. Furthermore, it was found that the larger compressive residual strain in the BFO(001) film leads to a 34% decrement in , which was believed to result from the widened band gap. PV property was also sensitive to phase and roughness, the formation of Bi O , and a roughened surface suppresses PV effect.Index Terms-Glass substrate, metallic underlayer, multiferroic BiFeO films, photovoltaic effect.

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Substrate influence on the optical and structural properties of pulsed laser deposited BiFeO3 epitaxial films

Cited by 62 publications

References 30 publications

Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition

Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition

Raman spectra and dielectric function of BiCrO3: Experimental and first-principles studies

Photovoltaic Property of Multiferroic ${\hbox{BiFeO}}_3$ Films With Different Textures on Glass Substrates

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Substrate influence on the optical and structural properties of pulsed laser deposited BiFeO3 epitaxial films

Cited by 62 publications

References 30 publications

Nanocrystalline Ferroelectric BiFeO3 Thin Films by Low-Temperature Atomic Layer Deposition

Nanocrystalline Ferroelectric BiFeO3 Thin Films by Low-Temperature Atomic Layer Deposition

Raman spectra and dielectric function of BiCrO3: Experimental and first-principles studies

Photovoltaic Property of Multiferroic ${\hbox{BiFeO}}_3$ Films With Different Textures on Glass Substrates

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Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition

Nanocrystalline Ferroelectric BiFeO₃ Thin Films by Low-Temperature Atomic Layer Deposition