The Power of SEM-EDS in Imaging and Elemental Analysis

SEM (Scanning Electron Microscope) equipped with EDS (Energy Dispersive X-ray Spectrometer) can capture detailed images and identify elements simultaneously on the surface of samples. For imaging, SEM is widely used since it needs minimal sample preparation and produces excellent resolution, unique contrast, and a large depth of field. When paired with an EDS system, elemental information of the imaged area can also be derived. SEM-EDS is ideal for imaging and elemental analysis applications requiring higher resolution than optical microscopy and identifying elemental make up. In SEM, an image is formed by scanning a focused electron beam, usually with energies of 1 to 20 keV, across a sample and detecting the ejected secondary or backscattered electrons.  The incident electron beam, when imparting energy to the sample, can cause emission of x-rays that are characteristic of the sample atoms. The energies of the x-rays are characterized using EDS to identify the elements in the sample. The typical spatial resolution of SEM imaging is about 5-10 nanometers.  SEM-based EDS is primarily a qualitative technique providing data from about a micrometer in diameter and a micrometer deep.