The effect of secondary electrons on radiolysis as observed by in liquid TEM: The role of window material and electrical bias

Lindsey A Bultema; Robert Bücker; Eike C Schulz; Friedjof Tellkamp; Josef Gonschior; R J Dwayne Miller; Günther H Kassier

doi:10.1016/j.ultramic.2022.113579

The effect of secondary electrons on radiolysis as observed by in liquid TEM: The role of window material and electrical bias

Ultramicroscopy. 2022 Oct:240:113579. doi: 10.1016/j.ultramic.2022.113579. Epub 2022 Jun 22.

Authors

Lindsey A Bultema¹, Robert Bücker², Eike C Schulz³, Friedjof Tellkamp¹, Josef Gonschior¹, R J Dwayne Miller⁴, Günther H Kassier⁵

Affiliations

¹ Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
² Centre for Structural Systems Biology, Department of Chemistry, University of Hamburg, Notkestrasse 85, 22607 Hamburg, Germany.
³ Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany; Universität Hamburg, HARBOR, Luruper Chaussee 149, 22761 Hamburg, Germany.
⁴ Departments of Chemistry and Physics, University of Toronto, Toronto, Canada. Electronic address: dmiller@lphys2.chem.utoronto.ca.
⁵ Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany. Electronic address: guenther.kassier@desy.de.

PMID: 35780682
DOI: 10.1016/j.ultramic.2022.113579

Abstract

The effect of window material on electron beam induced phenomena in liquid phase electron microscopy (LPEM) is an interesting yet under-explored subject. We have studied the differences of electron beam induced gold nanoparticle (AuNP) growth subject to three encapsulation materials: Silicon Nitride (Si₃N₄), carbon and formvar. We find Si₃N₄ liquid cells (LCs) to result in significantly higher AuNP growth yield as compared to LCs employing the other two materials. In all cases, an electrical bias of the entire LC structures significantly affected particle growth. We demonstrate an inverse correlation of the AuNP growth rate with secondary electron (SE) emission from the windows. We attribute these differences at least in part to variations in SE emission dynamics, which is seen as a combination of material and bias dependent SE escape flux (SEEF) and SE return flux (SERF). Furthermore, our model predictions qualitatively match electrochemistry expectations.

Keywords: Au nanoparticle growth; Carbon; Formvar; Liquid TEM; Secondary electrons; Si(3)N(4).