Electron Optic Documents

STEM-in-SEM (Scanning Transmission Electron Microscopy in an SEM) has become a popular technique for biologists, polymer scientists and materials scientists for its ease of use, cost effectiveness and high resolution. It is especially suited to investigating the internal structure of thin film (100-200nm) samples as well as size and shape of submicron to nanometer particles. With standard SEM imaging modes on bulk samples, there are limitations in the ultimate resolution that can be achieved due in part by the beam-sample interactions. With STEM-in-SEM, the sample is very thin and the interaction volume is small. Therefore, the resolution more closely approximates the diameter of the electron beam at the exit surface of the sample allowing for high resolution; using STEM with our state of the art FE SEMs, sub-nanometer resolution is easily achieved.

STEM-in-SEM (Scanning Transmission Electron Microscopy in an SEM) has become a popular technique for biologists, polymer scientists and materials scientists for its ease of use, cost effectiveness and high resolution. It is especially suited to investigating the internal structure of thin film (100-200nm) samples as well as size and shape of submicron to nanometer particles. With standard SEM imaging modes on bulk samples, there are limitations in the ultimate resolution that can be achieved due in part by the beam-sample interactions. With STEM-in-SEM, the sample is very thin and the interaction volume is small. Therefore, the resolution more closely approximates the diameter of the electron beam at the exit surface of the sample allowing for high resolution; using STEM with our state of the art FE SEMs, sub-nanometer resolution is easily achieved.

Imaging of nanostructured materials requires a new design of SEM that provides ultimate resolution for both imaging and microanalysis, combined with the ability to image any type of material. An innovative new SEM column design from JEOL Ltd. utilizes a hybrid lens (combination electrostatic and electromagnetic lenses) in conjunction with a Through-The-Lens (TTL) detection system to provide the user with ultimate imaging and analytical performance. The hybrid electrostatic/electromagnetic lens minimizes magnetic field effects at the sample and is relatively impervious to stray magnetic fields. The lens is characterized by low values for the spherical and chromatic aberration coefficients. Moreover, the proven Aberration Correction Lens (ACL) technology automatically maintains small probe size for both imaging and microanalysis.

SEM offers a unique ability to visualize specimen surface morphology (via secondary electron imaging), as well as obtain crystallographic or Z-contrast information (via backscatter electron imaging) while at the same time performing chemical composition analysis via energy dispersive spectroscopy (EDS). In the past, this simultaneous acquisition was often hindered by deficiencies in detector and column design, that would not allow sufficient count rates or sufficient resolution for adequate analysis at various working distances.