Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 27: Focus Session: Functional Metal Oxides for Novel Applications and Devices I (joint session HL/DS)

DS 27.7: Talk

Wednesday, March 18, 2020, 17:45–18:00, POT 81

Investigations on leakage current in epitaxial K0.5Na0.5NbO3 thin films grown by PLD — •Daniel Pfützenreuter, Julian Stöver, Klaus Irmscher, Jens Martin, and Jutta Schwarzkopf — Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin

KxNa1-xNbO3 is a lead-free, ferro- and piezoelectric compound, which offers a high potential for memory applications and sensors in thin films form. However, KxNa1-xNbO3 thin films often suffer from a high leakage current. This is assumed to be mainly attributed to the high volatility of the alkaline components at high temperatures, but also interface effects have to be regarded. Pulsed laser deposition (PLD) represents a suitable method for the epitaxial growth of K0.5Na0.5NbO3 films. In this study the impact of strain, film thickness and bottom electrode on vertical electric behaviour of epitaxially grown K0.5Na0.5NbO3 films is investigated. For this purpose, K0.5Na0.5NbO3 films were grown on SrRuO3 and La0.67Sr0.33MnO3 covered SrTiO3 and DyScO3 substrates as well as directly on SrTiO3:Nb substrates with a film thickness between 20 and 200 nm. While for small film thicknesses Ohmic charge transport is observed in I-V-measurements, the charge transport mechanism changes to pronounced Schottky like behaviour at thicker films. This transition is investigated in more detail by comparing the measured I-V curves with calculated ones for different mechanisms of current flow. Furthermore, we find a strong correlation between the lattice strain in the films and the kind of charge transport mechanism.