Local electronic transport across probe/ionic conductor interface in scanning probe microscopy

abstract

Charge carrier transport through the probe-sample junction can have substantial consequences for outcomes of electrical and electromechanical atomic-force-microscopy (AFM) measurements. For understanding physical processes under the probe, we carried out conductive-AFM (C-AFM) measurements of local current-voltage (I-V) curves as well as their derivatives on samples of a mixed ionic-electronic conductor Li1-xMn2O4 and developed an analytical framework for the data analysis. The implemented approach discriminates between contributions the highly resistive sample surface layer and the bulk with the account of ion redistribution in the field of the probe. It was found that, with increasing probe voltage, the conductance mechanism in the surface layer transforms from Pool-Frenkel to space-charge-limited current. The surface layer significantly alters the ion dynamics in the sample bulk under the probe, which leads, in particular, to a decrease of the effective electromechanical AFM signal associated with the ionic motion in the sample. The framework can be applied for the analysis of electronic transport mechanisms across the probe/sample interface as well as to uncover the role of the charge transport in the electric field distribution, mechanical, and other responses in AFM measurements of a broad spectrum of conducting materials.

keywords

CHARGE-LIMITED CURRENTS; ELECTROCHEMICAL STRAIN MICROSCOPY; PIEZORESPONSE FORCE MICROSCOPY; ION-TRANSPORT; THIN-FILMS; LIMN2O4; LITHIUM; SPECTROSCOPY; INJECTION; NANOMETER

subject category

Microscopy

authors

Romanyuk, KN; Alikin, DO; Slautin, BN; Tselev, A; Shur, VY; Kholkin, AL

Groups

G2 - Photonic, Electronic and Magnetic Materials

Projects

Degradation in Li-batteries: a Scanning Probe Microscopy Approach (LI-SPM)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

acknowledgements

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. The work was financially supported by the Portuguese Foundation for Science and Technology (FCT) within the project PTDC/CTM-ENE/6341/2014. It is also funded by national funds (OE), through FCT -Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. The authors thank Daniele Rosato (Robert Bosch, GmbH) for providing samples of Li -battery cathodes and useful discussions. Equipment of the Ural Center for Shared Use Modern nanotechnology of the Ural Federal University was used in the experiments. The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under the project #FEUZ-2020-0054.