Tuesday, June 14, 2011


The CMMP group at the Florida State University Department of Physics has a JEOL 5900 scanning electron microscope (SEM) that is available to the local research community. A small fee of $40/hour is assessed for usage of this instrument.

The JEOL 5900 has a maximum beam voltage of 30 kV. It is also a low voltage SEM, allowing one to control the beam voltage in increments of 100 V from 300 V to 2500 V. This is useful in imaging insulating materials without coating. The resolution at 30 kV and at a 10mm working distance is ~ 10 nm. In addition to imaging with secondary electrons (SEI) and backscattered electrons (BEI), an energy dispersive X-ray spectrometer (EDS) is available for quantitative elemental analysis and elemental maps.

SEM Advantages: fast; huge depth of field; large field of view; ability to image in SEI and BEI modes; low voltage imaging of insulating materials.

SEM Disadvantages: special sample preparation for biological and other "wet" samples; while lateral distances can be measured directly, vertical ones can not; no digital image processing tools to get Ra, bearings, feature depths, etc.

EDS Advantages: fast; elemental mapping; good accuracy with standards; good for defect analysis.

EDS Disadvantages: insensitive to light elements; poor energy resolution; spectral overlaps.

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