Stoichiometric, nonstoichiometric, and locally nonstoichiometric SrTiO{sub 3} films grown by molecular beam epitaxy
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
- Electro-Optics Center, Pennsylvania State University, Freeport, Pennsylvania 16229 (United States)
- Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
SrTiO{sub 3} films were grown by reactive molecular beam epitaxy to have varying degrees of both global and local cationic nonstoichiometries (with stoichiometry defined as a 1:1 ratio of Sr:Ti). Slight global excesses of Sr and Ti resulted in two-fold reconstructions in the reflection high-energy electron diffraction patterns along the [110] and [100] azimuths, respectively. Larger global nonstoichiometries (2:1 and 1:2 ratios) were also accommodated into the film's crystalline structure and affected the long-range crystalline order as observed in the x-ray diffraction patterns, both of which were related to the parent perovskite pattern. Local nonstoichiometries were introduced by depositing multiple monolayers (MLs) (from 2 to 33) of SrO and TiO{sub 2} in an alternating fashion, while maintaining the global SrTiO{sub 3} stoichiometry. These layered structures of SrO and TiO{sub 2} blocks inter-reacted during growth to form highly crystalline epitaxial SrTiO{sub 3}. Films grown in this manner with blocks thicker than 8 MLs were fully relaxed and, when the block thicknesses ranged between 8 and 10 MLs, the full widths at half maxima of 2{theta} peaks were narrower than the standard SrTiO{sub 3} films having blocks 1 ML thick.
- OSTI ID:
- 21064496
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 1; Other Information: DOI: 10.1063/1.2827992; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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