Hi Adam

the electric charge is produced by electron bombardment, by an electric field, or by mechanical stress. the charge produced as a result of trapping of carriers on the defects formed in the course of the dissipation of energy by the lattice. 

I think reading this paper would be helpful:

Charging phenomena on insulating materials: Mechanisms and applications

DOI: 10.1002/sca.4950120406

Regards

Amin

Hello Adam Baggott,

The SEM secondary electron sensor may be over-saturated by electrons when the reflected electrons are of high intensity. Then there are many bright areas (white dots or spots) on the image. To reduce the white areas in microscope management and the software to reduce the sensitivity and hence the illumination. Permanent sensing of the secondary electronic signal sensor should not be observed. This phenomenon is only temporary until the electrical signal is discharged. Naturally, the stress loads temporarily affect the electron emission, and hence the image to be captured.

If your specimens have conductive coating, then I doubt you will see any subtle charging effects. If you use ESEM for not coated specimens, then for crystals you can observe some interesting effects (google SEM, charge contrast).

Before we start to speculate (I have never realized any correlation between charging effects and lattice strain)...could you post one of your images? It is never good to talk about something which should exist but has been never seen.

Please rememeber that SE also collects BSE's which definitely image lattice strain because of the very sensitive channeling-in effects, see e.g. the attached paper. There are possibly other papers which at least report a roughly qualitative interpretation of channeling effects.

SE images may be influenced by lattice strain but I would expect a rather small effect. The observed charging might be also caused by a microscopically higher surface roughness caused by dislocation movements. And topography is the major factor for SE image contrast (as far as I know).

Article Diffraction effects and inelastic electron transport in angl...

If you are imaging a polished surface, it may be possible that the stressed region polished at a different rate, causing relief, and charging due to edge effect. Run your detector in topographical mode to see if there are regions of relief that could be responsible.