Scanning Electron Microscopy (SEM)

Scanning Electron Microscopy uses a focused electron beam to scan a solid sample from the optical to nanoscale range. Secondary electrons are generated in the sample and collected to create a 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 smaller than a nanometer for some instruments, but 3 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 imaging to observe elemental contrast
  • 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
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.

Instrument Emitter Low Vac Resolution ESEM EDS EBSD Other Features
FEI Nova NanoSEM 630 SEM FEG * 1.7 nm   *    
Thermo Fisher (FEI) Q250 Environmental SEM W * 10 nm * *   Temp. Controlled Stage
Thermo FIsher (FEI) Scios 2 FIB/SEM FEG * 2 nm   *   Cryo
FEI Helios NanoLab 660 FIB/SEM FEG   0.7 nm   * * Cryo

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