Mechanical strain engineering of dielectric tunability in polycrystalline SrTiO3 thin films

authors	Tkach, A; Okhay, O; Reaney, IM; Vilarinho, PM
nationality	International
journal	JOURNAL OF MATERIALS CHEMISTRY C
keywords	FERROELECTRICITY; CRYSTAL
abstract	Optimizing performance using low cost scalable processing and substrates is critical if functional oxide thin films are to achieve commercialisation. Here, we present a comprehensive investigation of the role of low cost Al2O3, SrTiO3, and MgO substrates in the structure, microstructure and electrical properties of SrTiO3 (ST) thin films, deposited by sol-gel processing. We demonstrate that the dielectric properties of polycrystalline ST films depend on the strain/stress induced by the substrates. ST films deposited on Al2O3/Pt substrates under a high tensile stress possess the smallest grain size and present the lowest value of the relative permittivity, er, with the lowest dielectric tunability. In contrast, ST films deposited on MgO/Pt substrates, under the highest compressive stress, have the highest value of er, tunability and polarization. It is thus demonstrated that for polycrystalline ST films the relative permittivity and dielectric tunability may be optimised through an induced compressive stress state.
publisher	ROYAL SOC CHEMISTRY
issn	2050-7526
year published	2018
volume	6
issue	10
beginning page	2467
ending page	2475
digital object identifier (doi)	10.1039/c8tc00414e
web of science category	Materials Science, Multidisciplinary; Physics, Applied
subject category	Materials Science; Physics
unique article identifier	WOS:000428997500008