Abstract
A systematic study on charging of carbon thin films under intense electron-beam irradiation was performed in a transmission electron microscope to identify the underlying physics for the functionality of hole-free phase plates. Thin amorphous carbon films fabricated by different deposition techniques and single-layer graphene were studied. Clean thin films at moderate temperatures show small negative charging while thin films kept at an elevated temperature are stable and not prone to beam-generated charging. The charging is attributed to electron-stimulated desorption (ESD) of chemisorbed water molecules from the thin-film surfaces and an accompanying change of work function. The ESD interpretation is supported by experimental results obtained by electron-energy loss spectroscopy, hole-free phase plate imaging, secondary electron detection and x-ray photoelectron spectroscopy as well as simulations of the electrostatic potential distribution. The described ESD-based model explains previous experimental findings and is of general interest to any phase-related technique in a transmission electron microscope.
Original language | English |
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Journal | Ultramicroscopy |
Volume | 184 |
Pages (from-to) | 252-266 |
Number of pages | 15 |
ISSN | 0304-3991 |
DOIs | |
Publication status | Published - 2018 |
Keywords
- Scanning transmission electron microscopy
- Transmission electron microscopy
- Electron-beam induced charging
- Thin film
- Phase plate
- Radiation damage
- Hole-free phase plate
- Volta phase plate