Angle selective backscattered electron contrast in the low-voltage scanning electron microscope: Simulation and...

Area of Science:

• Materials Science
• Electron Microscopy
• Nanotechnology

Background:

• Advanced detectors enhance imaging capabilities in low voltage scanning electron microscopes (LVSEM).
• Beam deceleration in LVSEM offers improved resolution and contrast for nanostructured materials.
• Understanding compositional contrast is crucial for analyzing complex material distributions.

Purpose of the Study:

• To predict and optimize imaging conditions for achieving purely compositional contrast in LVSEM.
• To model electron signal intensity using angle-selective back-scattered electron (BSE) detection.
• To experimentally validate simulation predictions on various carbon-based nanomaterials.

Main Methods:

• Utilizing Monte Carlo simulations to predict electron signal intensity under angle-selective BSE detection.
• Employing a concentric back-scattered (CBS) detector with and without a deceleration field.
• Experimental validation using amorphous carbon, copper, and complex nanostructured polymers (PNIPAM/PEGDA IPN, P3HT film).

Main Results:

• Accurate prediction of electron signal intensity for angle-selective BSE imaging in LVSEM.
• Experimental validation confirmed model predictions for compositional contrast.
• Successful mapping of nano-scale composition and crystallinity in complex nanostructured materials.

Conclusions:

• The developed model and detector system enable precise control over compositional contrast in LVSEM.
• This approach allows for detailed nanoscale mapping of material distribution, avoiding topographical artifacts.
• Optimized LVSEM imaging provides new insights into the structure of advanced carbon-based nanomaterials.