J.D. Adams, H. Gunstheimer, G. Fläschner, H. Hölschner, B. Hoogenboom
Nanosurf,
Switzerland
Keywords: AFM, photothermal actuation, nanomechanical analysis, high-throughput
Summary:
In many common methods for nanomechanical analysis with the atomic force microscope, the tip is brought in and out of sample interaction with a distance modulation. The force-distance curves generated may be analyzed to characterize sample properties such as elasticity and adhesiveness, making the atomic force microscope a powerful tool for nanoscale surface analysis. When the AFM scanner is used to generate this distance modulation, the frequency at which this modulation may be performed is limited by the scanner dynamics. In contrast, photothermal actuation offers the benefit of directly bending the cantilever to achieve tip-sample distance modulation at frequencies beyond scanner limitations. With a physical understanding of the photothermally actuated cantilever bending, we explain the cantilever response and propose a calibration procedure that converts the thermomechanical cantilever bending behavior into force curves understandable for analysis. We present the experimental validation of the method by measurements of varied samples and reference structures. This method enables nanomechanical mapping in a manner similarly quantitative to conventional methods, but at orders-of-magnitude higher frequencies, enabling higher throughput.