G-mode KPFM: Bringing kelvin probe into the information age

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. However, the technique is known to suffer from artifacts associated with non-ideality of bias feedback as well as being unsuitable for some voltage sensitive materials. Furthermore, in many applications, it is dynamic electrochemical processes which determine overall functionality, whereas KPFM can only measure static or quasistatic properties. Here we describe General acquistion (G)-Mode KPFM, which works by streaming the excitation signal and the photodetector signal straight to computer memory, bypassing the AFM controllers many filters and demodulation pathways. In this work, we outline a set of protocols for (a) denoizing (b) visualising and (c) quantifying the multidimensional datasets while preserving the temporal information on the tip-sample interactions. We investigate the veracity of the G-Mode KPFM approach for quantification of surface potential in two different ways. First we compare the single point surface potential values measured using G-Mode KPFM on a gold electrode whose surface potential is modulated with a known voltage. Afterwards we directly compare G-Mode KPFM imaging capabilities with conventional KPFM on a model test sample. In the future, G-KPFM while provide a real oppurtunity to explore dynamic processes taking place between tip and sample which is key towards developing a complete understanding of functionality in a range of systems including battery materials, photovoltaics and biosystems.