Why coating is necessary for SEM?

Coating is necessary for scanning electron microscopy (SEM) because it enhances the conductivity of non-conductive samples, preventing the buildup of charge during imaging. This charge accumulation can distort the electron beam and lead to poor-quality images. Additionally, coatings can improve surface detail visibility and contrast, allowing for more accurate analysis of the sample's morphology and composition. Common coatings include gold, platinum, and carbon, which provide a thin layer that is effective without significantly altering the sample.