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L. Ruiz‑Ortega, P. Mesquida, G. Schitter, B. Tang:
"Imaging and tracking an electrostatic charge micro-domain by Kelvin force microscopy as evidence of water adsorption on mica surface";
Current Applied Physics, 20 (2020), 12; 1391 - 1395.

Muscovite mica is a widely accepted substrate for scanning probe microscopy (SPM) investigations. However, mica has intrinsic properties that alter samples and obstruct their analysis due to free charges build-up, ionic exchange and water adsorption taking place at the surface. In addition to interfacial phenomena, there is a growing interest in electrostatic charges on insulators as they are crucial in diverse applications. Despite the high demand for studies of this nature, experimental set-ups capable of resolving charge build-up at the micro-scale are still scarce and technically limited. Here, we report the imaging of surface charge dissipation on freshly cleaved mica by Kelvin-probe Force Microscopy (KPFM). A local electrostatic charge micro-domain was generated by friction between an atomic force microscope (AFM) tip and mica, and its decay was tracked by two-dimensional mapping using KPFM. We found time-dependent charge dissipation, which is attributed to the adsorption of water molecules on mica surface.

Electrostatic charge, Scanning probe microscopy, Mica, Kelvin-probe force microscopy, Charge dissipation

http://dx.doi.org/10.1016/j.cap.2020.09.008