Full data acquisition in Kelvin Probe Force Microscopy: Mapping dynamic electric phenomena in real space

• Published in: Scientific reports Vol. 6; no. 1; p. 30557
• Main Authors: Collins, Liam, Belianinov, Alex, Somnath, Suhas, Balke, Nina, Kalinin, Sergei V, Jesse, Stephen
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 12.08.2016
• Subjects: Bias; Capacitance; Compression; Data acquisition; Electrostatic properties; Feedback; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Interfaces; Mapping; Microscopy
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep30557

Kelvin probe force microscopy (KPFM) has provided deep insights into the local electronic, ionic and electrochemical functionalities in a broad range of materials and devices. In classical KPFM, which utilizes heterodyne detection and closed loop bias feedback, the cantilever response is down-sampled to a single measurement of the contact potential difference (CPD) per pixel. This level of detail, however, is insufficient for materials and devices involving bias and time dependent electrochemical events; or at solid-liquid interfaces, where non-linear or lossy dielectrics are present. Here, we demonstrate direct recovery of the bias dependence of the electrostatic force at high temporal resolution using General acquisition Mode (G-Mode) KPFM. G-Mode KPFM utilizes high speed detection, compression, and storage of the raw cantilever deflection signal in its entirety at high sampling rates. We show how G-Mode KPFM can be used to capture nanoscale CPD and capacitance information with a temporal resolution much faster than the cantilever bandwidth, determined by the modulation frequency of the AC voltage. In this way, G-Mode KPFM offers a new paradigm to study dynamic electric phenomena in electroactive interfaces as well as a promising route to extend KPFM to the solid-liquid interface.