FIM operates by applying a high voltage to a finely sharpened metallic tip, creating an intense electric field at the apex. A gas, usually helium or neon, is introduced, and the electric field ionizes the gas atoms near the tip. The resulting ions are repelled from the tip and projected onto a detector screen, forming an image that represents the atomic arrangement on the surface of the tip. This method can achieve atomic resolution, making it an invaluable tool for nanoscale research.
