Scanning Electron Microscopy (SEM)

Scanning Electron Microscopy uses a focused electron beam to scan solid sample from the optical to nanoscale range. Secondary electrons are emitted from the sample and collected to create an area map of the secondary emissions. Since the intensity of secondary emission is dependent on local morphology, the area map is a magnified image of the sample. Spatial resolution is as high as 1.8 nanometers for some instruments, but 4 nm is typical for most. Backscattered electrons (BSE) and characteristic X-rays are also generated by the scanning beam and many instruments employ these signals for compositional analysis of the sample.

Typical Applications

• Secondary electron image for surface morphology
• Back-scattered image of material show contrast between areas with different elemental composition
• Environmental scanning electron microscope mode - Allows for in-situ heating and cooling experiments in the microscope

Sample Requirements

Sample requirements vary with instrument and analysis desired. Please ask the technical staff about the requirements for your project.

Related Techniques

• Energy Dispersive analysis (EDS)
• Electron Backscattered Diffractometry (EBSD)

Instrumentation

MCL maintains a few SEMs (see table below). For some of the microscopes beam deceleration or low vacuum mode can be used to study uncoated insulating and life science specimens. If you need help determining which instrument will best suit your needs please speak with a technical staff member.

(ESEM: Environmental SEM, EDS: Energy Dispersive Spectrometry, EBSD: Electron Back Scattered Diffractometry, BSE: Back Scattered Electrons)