Writing silica structures in liquid with scanning transmission electron microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Electron Microscopy

Background:

• Imaging nanoparticles in liquid requires specialized techniques to maintain sample integrity.
• Electron beam irradiation can induce changes in nanomaterials.

Purpose of the Study:

• To image silica nanoparticles in solution using STEM.
• To investigate the effects of electron beam irradiation on silica nanoparticles within a liquid cell.
• To explore the potential for nanoscale patterning using this method.

Main Methods:

• Utilized scanning transmission electron microscopy (STEM) with a liquid cell.
• Employed silicon nitride (SiN) membrane windows for sample containment.
• Correlated STEM findings with scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Main Results:

• Silica nanoparticles deposited in distinct patches on SiN membranes under electron beam irradiation.
• Deposit thickness showed a linear correlation with electron dose.
• Nanoparticle merging and dose rate-dependent surface roughness were observed.
• Sub-micrometer structures were patterned on SiN membranes in liquid.

Conclusions:

• Electron beam irradiation in STEM can induce controlled deposition and merging of silica nanoparticles in liquid.
• This technique allows for the writing of sub-micrometer structures on SiN membranes.
• The study demonstrates a novel method for in-situ nanoscale fabrication in liquid environments.