Scanning Electron Microscopy (SEM) spatial resolution

Scanning Electron Microscopy lab - in the Materials Characterization Lab at the Millennium Science Complex

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