PeakForce Tapping™ (PFT) and ScanAsyst™ (SA) are two Atomic Force Microsocope (AFM) imaging techniques that have been recently introduced by Bruker. In this application note we will explain the underlying physical background, fit PFT into the framework of existing AFM modes, and show the benefits of these new modes through application examples.
Why Were AFMs Previously Difficult to Use?
Let’s examine briefly the actual workflow necessary to run an AFM experiment. A typical session starts with sample preparation and AFM mode selection. The latter sometimes dictating the former. Once the sample is ready, the AFM has to be set up (i.e., the sample has to be mounted, the scan mode selected, a tip inserted, and the detection system aligned). After that, the system has to be brought into “feedback” and the feedback constantly tuned by the operator according to the scan conditions to ensure proper operation. Following the successful acquisition of an image it has to be analyzed and presented.
If one analyzes this typical workflow across applications and user experience, the crucial step is the actual adjustment of the AFM feedback parameters. It is by far the most time-consuming and nuanced part of an AFM experiment, and thus offers the most potential benefit to the user for automation. In short, ScanAsyst automatically provides you with consistent, expert-quality results independent of user experience.
To put the capability of ScanAsyst into context, it is useful to examine the existing AFM scan modes to better understand how ScanAsyst, and its underlying mode PeakForce Tapping fit into the modes hierarchy.