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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 5: Thin oxides and oxide layers (joint session DS/KFM)

KFM 5.2: Vortrag

Montag, 18. März 2024, 09:45–10:00, A 053

Defect and Strain Engineering in SrTiO3 and CaTiO3 Thin Films Epitaxially Grown by Metal Organic Vapor Phase Epitaxy (MOVPE) — •Mohamed Abdeldayem, Changming Liu, Izaz-Ali Shah, Andreas Fiedler, Martin Albrecht, and Jutta Schwarzkopf — Leibniz-Institut für Kristallzüchtung, Berlin, Germany

Neuromorphic devices attempt to imitate the human brain, and replace the conventional computer design to meet the demands of energy efficiency, and learning capacity. Memristive devices are a leading candidate to provide the physical properties needed for an artificial neural network. Here, we report a model in SrTiO3 and CaTiO3 thin films where resistive switching mechanism is based on polar nano-regions created by the formation of Ti anti-site defects in A-cation deficient growth regime. SrTiO3 and CaTiO3 thin films were grown epitaxially by metal-organic vapor phase epitaxy in which growth takes place near thermodynamic equilibrium and high oxygen partial pressure. This provides well-ordered epitaxial films with low defect density and negligible amount of oxygen vacancies. Moreover, chemical elements can be independently controlled by controlling the precursor fluxes in the gas phase, which enables the growth of stoichiometric and intentionally off-stoichiometric films. HRXRD, and AFM were used to verify epitaxial growth of high structural quality films with smooth surfaces. STEM-HAADF was utilized for detailed microscopic structural investigation, and showed the high homogeneity of stoichiometric films opposite to the intentionally defect ones with cloudy contrast and defect clustering.

Keywords: Thin films; Neuromorphic Computing; MOVPE; epitaxy; resistive switching