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 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

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 FESEM	FEG	*	1.7 nm		*		Beam Decelaration
FEI Quanta 200 Environmental SEM	W	*	10 nm	*	*		Temp. Controlled Stage
FEI Quanta 2003D FIB/SEM	W	*	10 nm
FEI Helios NanoLab 660 FIB/FESEM	FEG		0.7 nm		*	*	Beam Deceleration, Cryo