Fast Specimen Boundary Tracking and Local Imaging with Scanning Probe Microscopy

Abstract

An efficient and adaptive boundary tracking method is developed to confine area of interest for high-efficiency local scanning. By using a boundary point determination criterion, the scanning tip is steered with a sinusoidal waveform while estimating azimuth angle and radius ratio of each boundary point to accurately track the boundary of targets. A local scan region and path are subsequently planned based on the prior knowledge of boundary tracking to reduce the scan time. Boundary tracking and local scanning methods have great potential not only for fast dimension measurement but also for sample surface topography and physical characterization, with only scanning region of interest. The performance of the proposed methods was verified by using the alternate current mode scanning ion-conductance microscopy, tapping, and PeakForce modulation atomic force microscopy. Experimental results of single/multitarget boundary tracking and local scanning of target structures with complex boundaries demonstrate the flexibility and validity of the proposed method.

Advanced in-situ electrochemical scanning probe microscopies in electrocatalysis

“…The ion current is highly sensitive to tip-to-sample separation, and three basic scanning modes have been developed: non-modulated [148], modulated [149][150][151], and hopping modes [152][153][154]. Significant advances have been witnessed in instrumentation [155,156], scan protocols [117,155,157], and algorithm improvements [158,159] to reduce the scan time and achieve higher resolution.…”

Scanning Ion Conductance Microscopy

“…Further, because BDA can depict the sample boundary in a scan area, this method is also able to decrease the scan time by limiting the scan area to the regions of interest. For instance, Xie and coworkers optimized scanning routines after determining the boundary of the sample and reduced the scan time …”

“…115 The feasibility of this approach was demonstrated for oligodendrocyte precursors, but this algorithm is limited to cells with a bipolar conformation. Wen et al proposed a universal boundary determination algorithm for more complicated samples, 116 in which a boundary point determination criteria (BPDC) was setup based on the height difference between arbitrary adjacent points. Briefly, a threshold Δ thre was determined and only adjacent points with height difference larger than Δ thre were considered as the boundary between the features of interest and the substrate.…”

“…For instance, Xie and coworkers optimized scanning routines after determining the boundary of the sample and reduced the scan time. 116…”