Secondary Electron Emission from Surfaces with Small Structure

TL;DR

This paper investigates how small surface structures, especially at the nanoscale, can significantly increase secondary electron emission yields and alter their energy dependence, impacting technological applications.

Contribution

It demonstrates that nanoscale surface structures can greatly enhance SEE yield and challenges the universal energy dependence assumption for structured surfaces.

Findings

Nanoscale structures can increase SEE yield by over 100%.

SEE yield dependence on primary electron energy varies with surface structure.

Conditions for applying conventional SEE models are derived.

Abstract

It is found that for objects possessing small surface structures with differing radii of curvature the secondary electron emission (SEE) yield may be significantly higher than for objects with smooth surfaces of the same material. The effect is highly pronounced for surface structures of nanometer scale, often providing a more than 100% increase of the SEE yield. The results also show that the SEE yield from surfaces with structure does not show an universal dependence on the energy of the primary, incident electrons as it is found for flat surfaces in experiments. We derive conditions for the applicability of the conventional formulation of SEE using the simplifying assumption of universal dependence. Our analysis provides a basis for studying low-energy electron emission from nano structured surfaces under a penetrating electron beam important in many technological applications.