[PDF]    http://dx.doi.org/10.3952/physics.v56i3.3366

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 56, 173–181 (2016)

Rūta Mackevičiūtėa, Šarūnas Bagdzevičiusa, Maksim Ivanova, Barbara Fraygolab, Robertas Grigalaitisa, Nava Setterb, and Jūras Banysa
aFaculty of Physics, Vilnius University, Saulėtekio 9, LT-10222 Vilnius, Lithuania
bCeramics Laboratory, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
E-mail: ruta.mackeviciute@ff.vu.lt

Received 5 February 2016; revised 1 March 2016; accepted 21 June 2016

Thin epitaxial films have a great potential to be used in real life applications, such as oxide-on-silicon. However, they often contain a large amount of defects, leading to an enhanced electrical conductivity. This could be desirable in some applications (i. e. memristors), but the mechanism is not fully understood. Here we report on the investigation of epitaxial barium strontium titanate thin films deposited on strontium titanate single crystal substrates (Ba0.7Sr0.3TiO3/SrRuO3//SrTiO3 heterostructures) with a controlled epitaxial strain. The impedance analysis allowed us to propose a model, which explains changes in the temperature dependence of the conductivity based on the strain-dependent anisotropic change of electron/hole mobility.
Keywords: thin films, impedance spectroscopy, electron mobility, ferroelectrics
PACS: 77.55.-g, 84.37.+g, 73.50.Gr, 77.80.B-


Rūta Mackevičiūtėa, Šarūnas Bagdzevičiusa, Maksim Ivanova, Barbara Fraygolab, Robertas Grigalaitisa, Nava Setterb, Jūras Banysa
aVilniaus universiteto Kietojo kūno elektronikos katedra, Vilnius, Lietuva
bŠveicarijos federalinis technologijos institutas (EPFL), Lozana, Šveicarija

Plonieji epitaksiniai sluoksniai yra patrauklūs įvairiems komerciniams taikymams, pavyzdžiui, silicio lustams su integruotomis oksidų heterostruktūromis. Deja, defektų koncentracija juose dažniausiai būna didelė, o tokie sluoksniai – elektriškai laidūs. Tai gali būti naudinga kai kuriems taikymams (pvz., memristoriuose), tačiau pats laidumo mechanizmas nėra iki galo suprastas. Straipsnyje pateikiame epitaksinių plonųjų bario stroncio titanato sluoksnių ant kristalinio stroncio titanato padėklo (Ba0.7Sr0.3TiO3/SrRuO3//SrTiO3 heterostruktūros) tyrimus kontroliuojant epitaksinius įtempimus. Remiantis elektrinės pilnutinės varžos analize, pateiktas teorinis modelis, paaiškinantis temperatūrinę elektrinio laidumo elgseną įtempimų sukeltu anizotropiniu elektronų / skylių judrio kitimu.

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