Scanning Electron Microscope (SEM) Introduction

Scanning Electron Microscope (SEM)

• The primary function of an SEM is to produce high-resolution images of the sample surface by scanning it with a focused beam of electrons.

Electron-Sample Interactions

• Signals derived from electron-sample interactions in an SEM can reveal information about the sample's topography, morphology, and composition.
• These interactions can produce a range of signals, including secondary electrons, backscattered electrons, and X-rays, which provide valuable information about the sample.

Point Analysis

• The SEM is capable of analyzing the composition of the sample at selected point locations, enabling the identification of elemental distributions and chemical compositions.

Energy Dissipation

• The kinetic energy from accelerated electrons in an SEM is dissipated in a solid sample through heat generation, causing the sample to warm up.

EDS

• EDS stands for Energy-Dispersive Spectroscopy, which is a capability of an SEM that enables the analysis of the elemental composition of a sample.

Contrast in Composition

• The X-ray signal is most valuable for illustrating contrasts in composition in multiphase samples, as it provides information about the elemental distribution.

Essential Component

• The essential component of all SEMs is the electron column, which includes the electron source and detectors for all signals of interest.

Inelastic Collisions

• Inelastic collisions of the incident electrons with electrons in discrete orbitals (shells) of atoms in the sample produce X-rays.

Non-Destructive Analysis

• SEM analysis is considered 'non-destructive' because the sample is not damaged or altered during the analysis process.

EBSD

• SEMs equipped with diffracted backscattered electron detectors (EBSD) can be used to examine the crystal structure and orientation of materials.

Learn about the basics of Scanning Electron Microscope (SEM), including its functionality and potential magnification. Understand how SEM uses electron beams to scan a sample's surface and record information about the interaction, creating a magnified image.