3D Simulation of AFM-IR Nanoscale Chemical Imaging

Abstract

Nanoscale chemical imaging through Atomic Force Microscopy-based Infrared Spectroscopy (AFM-IR) is pivotal for investigating the intricate structures and chemical compositions of materials and biological samples. Despite its significance, a critical element is currently absent: an analytical model specifically tailored for AFM-IR nanoscale chemical imaging. The development of such a model would significantly enhance our ability to comprehend the theoretical underpinnings of our experiments, improve result interpretation, and optimize experimental parameters. In this work, we propose the introduction of a 3D analytical model considering material properties and laser parameters and substantiated by experiments. Unique bilayer SU-8 and polymethyl methacrylate (PMMA) samples with various pattern sizes were prepared. The spatial resolution and intensity are notably influenced by the pattern geometry and size. Moreover, augmenting laser power and pulse width leads to increased signal intensity and depth sensitivity. Our research uniquely contributes to the comprehension and control of nanoscale chemical processes, encompassing factors like resolution and sensitivity.