Exploration of AFM Imaging Artifacts Occurring at Sharp Surface Features When Using Short Carbon Nanotube Probes and Possible Mitigation With Real-Time Force Spectroscopy

We present an overview of four types of imaging artifacts that can occur during characterization of sharp sample topographies with intermittent contact atomic force microscopy (AFM) when using short nanotube probes (⁠$<100nm$ in length). We discuss the causes behind these artifacts, as well as their implications in the context of nanomanufacturing, and explore theoretically their mitigation using AFM techniques that can perform simultaneous imaging and spectroscopy. In particular, we focus on the experimentally validated spectral inversion method [Stark et al., 2002, “Inverting Dynamic Force Microscopy: From Signals to Time-Resolved Interaction Forces,” Proc. Natl. Acad. Sci. U.S.A., 99, pp. 8473–8478; Sahin et al., 2007, “An Atomic Force Microscope Tip Designed to Measure Time-Varying Nanomechanical Forces,” Nat. Nanotechnol., 2, pp. 507–514] and on a recently proposed dual-frequency-modulation method [Chawla and Solares, 2009, “Single-Cantilever Dual-Frequency-Modulation Atomic Force Microscopy,” Meas. Sci. Technol., 20, p. 015501], which has been demonstrated within computational simulations and is under experimental implementation in our laboratory. We discuss the capabilities and limitations of each of these approaches as well as possible areas of future development.