Initial growth stages of epitaxial BaTiO3 films on vicinal SrTiO3 (001) substrate surfaces

Visinoiu, Alina; Alexe, Marin; Lee, Ho Nyung; Zakharov, Dmitri N.; Pignolet, A.; Hesse, D.; Gösele, U.

doi:10.1063/1.1478800

Cited by 50 publications

(26 citation statements)

References 22 publications

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“…Figs. 3(a) and (b) summarize the evolution of surface and interface roughness in situ from superlattices with d ¼ 2; 6, and 20 nm against N. From the multilayer stack with the dp6 nm and N ¼ 125; the surface and interface roughness are maintained at a value about 0.28 nm ($0.25 nm for a bare STO substrate); this condition might be a consequence of the repetition of two-dimensional nucleation and growth of BTO and LNO sublayers on the flat terrace of the STO substrate, as proposed by Visinoiu et al [14] and Terashima et al [15]. As d reaches 20 nm hence larger than the critical thickness, the surface and interface roughness increase largely relative to that with dp6 nm; due to strain relief in the multilayer stack.…”

Section: Article In Pressmentioning

confidence: 96%

Real-time X-ray study of roughness scaling in the initial growth of epitaxial BaTiO3/LaNiO3 superlattices

Liang

Lee

Liu

et al. 2005

Journal of Crystal Growth

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Section: Article In Pressmentioning

confidence: 96%

Real-time X-ray study of roughness scaling in the initial growth of epitaxial BaTiO3/LaNiO3 superlattices

Liang

Lee

Liu

et al. 2005

Journal of Crystal Growth

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“…A variety of deposition techniques including molecular-beam epitaxy (MBE) [5,6], laser MBE [7], atomic layer MOCVD [8], and pulsedlaser deposition [9,10] have been successfully used to grow epitaxial superlattice films of ferroelectric oxides. For these methods, a high temperature ($650 1C) is necessary to obtain epitaxial superlattice films of high quality [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effects of substrate temperature on the physical properties of strained BaTiO3/LaNiO3 artificial superlattices

Liang¹,

Liang²

2005

Journal of Crystal Growth

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“…This is, however, true only for films with thicknesses below a certain critical value (t c ), above which the strain relaxation via defect formation occurs. This thickness depends on the lattice mismatch between the film and the substrate [8,9]: for example, in BaTiO 3 on SrTiO 3 (in-plane mismatch of 2.4%) a t c ≈ 2-4 nm has been experimentally determined [10,11]. But at such small film thicknesses polarization measurements are hindered by high tunnelling and/or leakage currents.…”

mentioning

confidence: 99%

Suppressed Dependence of Polarization on Epitaxial Strain in Highly Polar Ferroelectrics

et al. 2007

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A combined experimental and computational investigation of coupling between polarization and epitaxial strain in highly polar ferroelectric PbZr 0.2 Ti 0.8 O 3 (PZT) thin films is reported. A comparison of the properties of relaxed (tetragonality c/a ≈ 1.05) and highly-strained (c/a ≈ 1.09) epitaxial films shows that polarization, while being amongst the highest reported for PZT or PbTiO 3 in either film or bulk forms (P r ≈ 82 μC/cm 2 ), is almost independent of the epitaxial strain. We attribute this behavior to a suppressed sensitivity of the A-site cations to epitaxial strain in these Pb-based perovskites, where the ferroelectric displacements are already large, contrary to the case of less polar perovskites, such as BaTiO 3 . In the latter case, the A-site cation (Ba) and equatorial oxygen displacements can lead to substantial polarization increases.Epitaxial strain, induced in thin films due to lattice mismatch between the material and the substrate, results in enhanced properties and device performance for many materials. Examples include a higher operation speed and lower power consumption in strain-engineered semiconductor-based devices [1] and a large enhancement of ferroelectric and dielectric responses in certain complex oxide perovskites [2][3][4][5][6]. Therefore, epitaxial strain is recognized as a useful tool to influence materials properties and it is tempting to assume that such strong sensitivity to epitaxial strain is common to all perovskite compounds.However, recent computational studies suggest that this is not universally true [7], while an experimental confirmation of such nonuniversality is a formidable task due to limitations explained below. Moreover, the fundamental mechanisms responsible for the coupling between epitaxial strain and ferroelectric polarization in thin films are not yet fully understood, although it is quite clear that they should be manifested most profoundly in coherently grown thin films. In such films misfit dislocation formation is energetically and/or kinetically prohibited and therefore reduction of the polarization by pinning of dipoles by defects is unlikely. This is, however, true only for films with thicknesses below a certain critical value (t c ), above which the strain relaxation via defect formation occurs. This thickness depends on the lattice mismatch between the film and the substrate [8,9]: for example, in BaTiO 3 on SrTiO 3 (in-plane mismatch of 2.4%) a t c ≈ 2-4 nm has been experimentally determined [10,11]. But at such small film thicknesses polarization measurements are hindered by high tunnelling and/or leakage currents. A strong influence of depolarization fields, originating from the incomplete screening of polarization [12], and a reduction of atomic displacements in the vicinity of interfaces [13] may also mask the intrinsic effects. Therefore, a careful characterization of strain effects is most reliably achieved in a system with a fairly small lattice mismatch with the substrate and, consequently, large t c (e.g., several tens of nanometr...

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Initial growth stages of epitaxial BaTiO3 films on vicinal SrTiO3 (001) substrate surfaces

Cited by 50 publications

References 22 publications

Real-time X-ray study of roughness scaling in the initial growth of epitaxial BaTiO3/LaNiO3 superlattices

Real-time X-ray study of roughness scaling in the initial growth of epitaxial BaTiO3/LaNiO3 superlattices

Effects of substrate temperature on the physical properties of strained BaTiO3/LaNiO3 artificial superlattices

Suppressed Dependence of Polarization on Epitaxial Strain in Highly Polar Ferroelectrics

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