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Title: Layer-by-Layer and Pseudo-Two-Dimensional Growth Modes for Heteroepitaxial BaTiO 3 Films by Exploiting Kinetic Limitations

Abstract

Pulsed laser deposition has enabled formation of highly oxidized and strained BaTiO{sub 3} films on SrTiO{sub 3} substrates in a layer-by-layer growth mode to thicknesses of 125 nm. Balancing thermodynamics and diffusion lengths enables controlled growth at the higher oxygen pressures required. Growth above 800 C produces an array of uniform pseudo-two-dimensional islands on single-step terraces which are independent of film thickness and correlated with threading dislocations. Control over growth modes is enabled by the manipulation of diffusion lengths and produces films with morphologies with broad applicability for fabrication of high-quality oxide films and self-assembled nanostructures.

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
932092
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 91
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; BARIUM OXIDES; TITANIUM OXIDES; DEPOSITION; STRONTIUM OXIDES; DIFFUSION LENGTH; DISLOCATIONS; KINETICS; NANOSTRUCTURES; SUBSTRATES; THERMODYNAMICS; BaTiO3 growth

Citation Formats

Shin, Junsoo, Kalinin, Sergei V, Borisevich, Albina Y, Plummer, E Ward, and Baddorf, Arthur P. Layer-by-Layer and Pseudo-Two-Dimensional Growth Modes for Heteroepitaxial BaTiO3 Films by Exploiting Kinetic Limitations. United States: N. p., 2007. Web. doi:10.1063/1.2790477.
Shin, Junsoo, Kalinin, Sergei V, Borisevich, Albina Y, Plummer, E Ward, & Baddorf, Arthur P. Layer-by-Layer and Pseudo-Two-Dimensional Growth Modes for Heteroepitaxial BaTiO3 Films by Exploiting Kinetic Limitations. United States. doi:10.1063/1.2790477.
Shin, Junsoo, Kalinin, Sergei V, Borisevich, Albina Y, Plummer, E Ward, and Baddorf, Arthur P. Mon . "Layer-by-Layer and Pseudo-Two-Dimensional Growth Modes for Heteroepitaxial BaTiO3 Films by Exploiting Kinetic Limitations". United States. doi:10.1063/1.2790477.
@article{osti_932092,
title = {Layer-by-Layer and Pseudo-Two-Dimensional Growth Modes for Heteroepitaxial BaTiO3 Films by Exploiting Kinetic Limitations},
author = {Shin, Junsoo and Kalinin, Sergei V and Borisevich, Albina Y and Plummer, E Ward and Baddorf, Arthur P},
abstractNote = {Pulsed laser deposition has enabled formation of highly oxidized and strained BaTiO{sub 3} films on SrTiO{sub 3} substrates in a layer-by-layer growth mode to thicknesses of 125 nm. Balancing thermodynamics and diffusion lengths enables controlled growth at the higher oxygen pressures required. Growth above 800 C produces an array of uniform pseudo-two-dimensional islands on single-step terraces which are independent of film thickness and correlated with threading dislocations. Control over growth modes is enabled by the manipulation of diffusion lengths and produces films with morphologies with broad applicability for fabrication of high-quality oxide films and self-assembled nanostructures.},
doi = {10.1063/1.2790477},
journal = {Applied Physics Letters},
number = ,
volume = 91,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • This article was originally published online and in print with an incorrect profile in Fig. 1 (b, bottom) on page 2. The correct radial profile peaks at zero radius, differentiated from the "pseudo-2D" growth.
  • The Fe/BaTiO{sub 3} interface is a prototypical artificial multiferroic system displaying purely electronic magnetoelectric effects at room temperature. As magneto-electric coupling is essentially localized at the interface, the properties of the very first Fe layers in contact with BaTiO{sub 3} play a major role. In this paper, we investigate, by using X-ray photoemission spectroscopy and photoelectron diffraction, the in-situ growth, by molecular beam epitaxy, of ultrathin Fe films (∼7 monolayers) on a BaTiO{sub 3}/SrTiO{sub 3}(001) template. We found that growing the Fe films above room temperature (373 K) is essential in order to avoid island growth and obtain a continuous film.more » Post-annealing up to 473 K improves the film crystallinity but prevents chemical interdiffusion and roughening. Just an interfacial monolayer of oxidized iron is detected in these conditions, which appears as an unavoidable consequence of the Fe/BaTiO{sub 3} chemical interaction. Its active role in magnetoelectric coupling must be carefully taken into account to correlate theoretical predictions and experiments.« less
  • The microstructure evolution of heteroepitaxial BaTiO{sub 3} (BTO) thin films grown on single crystal (001) SrTiO{sub 3} (STO) under Ne irradiation at room temperature was systematically investigated with special attention given to the behavior at the BTO/STO interface. Cross sectional transmission electron microscope investigations reveal that amorphization occurs at the top BTO film region. BTO grains in the dimensions of 10-20 nm survived the irradiation damage and maintained their original crystal orientation. Other irradiation-induced defects such as dislocation loops and defect clusters were observed only at the portion of the BTO thin film near the interface, but not at themore » STO side of the bilayer. Atomic calculations find that the energetics of defects are very similar on each side of the BTO/STO interface, suggesting that the interface will not significantly modify radiation damage evolution in this system, in agreement with the experimental observations. These results support the hypothesis we presented in previous work about the role of coherent interfaces on radiation damage evolution.« less
  • We investigated infrared-active phonons of CaTiO3, SrTiO3, BaTiO3, and Ba0.5Sr0.5TiO3 thin films, and a (BaTiO3)5/(SrTiO3)5 artificial superlattice by a Fourier transform infrared spectrometer with a grazing angle (48{sup o}) incident reflectance method. The longitudinal phonon energies of the thin films were different from those of the bulk material due to the lattice strain of the substrate. The Ba0.5Sr0.5TiO3 thin film and (BaTiO3)5/(SrTiO3)5 superlattice showed different phonon modes due to structural discrepancies, even though their chemical compositions are similar. The Ba0.5Sr0.5TiO3 thin film showed a single phonon energy lying between the phonon energies of BaTiO3 and SrTiO3 thin films, while themore » (BaTiO3)5/(SrTiO3)5 superlattice well preserved the characteristic phonon modes of BaTiO3 and SrTiO3 thin films.« less