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 investigation of the internal structure of thin film (50-100nm) samples as well as size and shape of submicron to nanometer particles. With standard SEM imaging modes and EDS analysis on bulk samples, there are limitations in the ultimate resolution that can be achieved due in part to the beam-sample interactions. With STEM-in-SEM, the sample is very thin and the interaction volume is greatly reduced, which allows for sub-nanometer resolution and nanoscale analysis. One of the main challenges to EDS analysis using STEM-in-SEM is how to reduce the hard X-ray contribution from the detector and chamber (generally peaks from Al and Si). JEOL has designed a dedicated Analytical holder with a carbon retainer that greatly reduces these spurious peaks allowing for more accurate analytical data.

The ability to increase the probe current for fast microanalysis, while still maintaining a small spot size and small volume of excitation for high resolution, has been the holy grail of microanalysis in SEM. One of the unique features of JEOL’s FE SEMs is the patented Aperture Angle Control Lens (ACL). This lens automatically optimizes for both high resolution imaging at low probe currents and high spatial resolution X-ray analysis at high probe currents with a seamless transition between the two. This is essential for rapid analysis and superb image quality and is particularly true for low kV microanalysis. The ACL works by considering effects of all aberrations (spherical, chromatic and diffraction limitations) on spot size and automatically optimizing the convergence angle.

Wet specimens are notoriously difficult to image in scanning electron microscopes (SEM) owing to evaporation from the required vacuum of the specimen chamber. Traditionally, this issue has been addressed by increasing the specimen chamber pressure. Unfortunately, observation under high specimen chamber pressure cannot prevent the initial evaporation effects. The wet cover method, where the original surface water is retained (and, therefore, considered wet), provides a way to introduce and subsequently image specimens that are sensitive to evaporation within a SEM, while preventing evaporation-related damage, and to observe interesting specimen–water interactions.

JEOL’s Particle Analysis Software 3 (PA3) enhances the capability of your analytical SEM by automating the detection, EDS analysis and classification of particles, grains or other features in your samples. Fully integrated with our SEM-EDS systems, PA3 increases throughput and productivity by providing fast, unattended measurements across large areas of a sample, or multiple samples.

Phase Analysis provides a new level of automation to your JEOL EDS data analysis and interpretation workflows

This Polymer note introduces a broad range of instruments used for polymer analysis and their applications.

When a sample is exposed to the electron beam in a scanning electron microscope a variety of signals are generated. X-rays being one of those signals that can provide valuable insight into a materials chemical makeup. The collected X-ray signal includes background X-ray radiation and more importantly, X-rays of specific energies, that are characteristic of the elements present in the sample. For this reason, an energy dispersive X-ray detector (EDS) is one of the most common detectors that is added to a scanning electron microscope (SEM). It is used to not only determine the elements present in a sample but in many instances can give insight to the quantity as well as the spatial distribution of these elements over very small volumes.

The first commercially available SEM was introduced over 50 years ago and to this day there is still no internationally accepted standard for determining SEM resolution. To add to the confusion, each SEM manufacturer relies on their own sample and methods for determining resolution.

The first commercially available SEM was introduced over 50 years ago and to this day there is still no internationally accepted standard procedure for determining the resolution in an SEM image. To add to the confusion, each SEM manufacturer relies on their own sample and methods for determining resolution. Defining the edge of a particle manually is also always subjective in nature; values will differ from one person to the next based on how that person interprets or ‘sees’ the edge of a particle.

In scanning electron microscopy (SEM), conductive coatings are commonly applied to the surface of insulating or beam sensitive materials such as biologic specimens, polymers, ceramics, geologic specimen, and semiconductors to dissipate charge build-up or reduce structural damage resulting from interaction with the electron beam. There are a wide variety of commercially available coating materials, including metals such as gold, platinum and iridium and non-metals including carbon. But which, if any, is right for you? Here we discuss when it is appropriate to add a conductive coating to insulating or beam sensitive materials and how to pick the best coating material for your applications.