Field Emission Microscopy (FEM) is a high-resolution imaging technique used to visualize the surface of materials at the atomic level. It operates by applying a strong electric field to a sharp metal tip, which causes electrons to be emitted from the tip and focused onto a detector. This allows researchers to obtain detailed images of the surface topography and electronic properties of various materials. FEM is particularly useful in studying semiconductors, nanostructures, and catalysts. By providing insights into surface defects and electronic behavior, it aids in the development of advanced materials and technologies, including nanoelectronics and energy storage systems.