Breaking the Time Barrier in Kelvin Probe Force Microscopy: Fast Free Force Reconstruction Using the G‑Mode Platform

• Published in: ACS nano 2017-09, Vol.11 (9), p.8717-8729
• Main Authors: Collins, Liam, Ahmadi, Mahshid, Wu, Ting, Hu, Bin, Kalinin, Sergei V, Jesse, Stephen
• Format: Article
• Language: English
• Subjects: NANOSCIENCE AND NANOTECHNOLOGY
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.7b02114

Atomic force microscopy (AFM) offers unparalleled insight into structure and material functionality across nanometer length scales. However, the spatial resolution afforded by the AFM tip is counterpoised by slow detection speeds compared to other common microscopy techniques (e.g., optical, scanning electron microscopy, etc.). In this work, we develop an ultrafast AFM imaging approach allowing direct reconstruction of the tip-sample forces with ∼3 order of magnitude higher time resolution than is achievable using standard AFM detection methods. Fast free force recovery (F3R) overcomes the widely viewed temporal bottleneck in AFM, that is, the mechanical bandwidth of the cantilever, enabling time-resolved imaging at sub-bandwidth speeds. We demonstrate quantitative recovery of electrostatic forces with ∼10 μs temporal resolution, free from influences of the cantilever ring-down. We further apply the F3R method to Kelvin probe force microscopy (KPFM) measurements. F3R-KPFM is an open loop imaging approach (i.e., no bias feedback), allowing ultrafast surface potential measurements (e.g.,