Development of a Practicable Digital Pulse Read-Out for Dark-Field STEM
Citation:
Mullarkey, T. and Downing, C. and Jones, L., Development of a Practicable Digital Pulse Read-Out for Dark-Field STEM, Microscopy and Microanalysis, 2021, 99 - 108Download Item:
Abstract:
When characterising beam-sensitive materials in the scanning transmission electron microscope (STEM), low-
dose techniques are essential for the reliable observation of samples in their true state. A simple route to
minimise both the total electron-dose and the dose-rate is to reduce the electron beam-current and/or raster the
probe at higher speeds. At the limit of these settings, and with current detectors, the resulting images suffer
from unacceptable artefacts including; signal-streaking, detector-afterglow, and poor signal-to-noise ratios
(SNR). In this manuscript we present an alternative approach to capture dark-field STEM images by pulse-
counting individual electrons as they are scattered to the annular dark-field (ADF) detector. Digital images
formed in this way are immune from analogue artefacts of streaking or afterglow and allow clean, high-SNR
images to be obtained even at low beam-currents. We present results from both a ThermoFisher FEI Titan G2
operated at 300kV and a Nion UltraSTEM200 operated at 200kV, and compare the images to conventional
analogue recordings. ADF data are compared with analogue counterparts for each instrument, a digital
detector-response scan is performed on the Titan, and the overall rastering efficiency is evaluated for various
scanning parameters.
Author's Homepage:
http://people.tcd.ie/jonesl1
Author: Jones, Lewys
Type of material:
Journal ArticleCollections
Series/Report no:
Microscopy and Microanalysis;Availability:
Full text availableKeywords:
beams, scanning transmission electron microscopy, low-dose imaging, Scanning transmission electron microscopy, Low-dose imaging, Electron counting, Annular dark-field (ADF) imagingDOI:
http://dx.doi.org/10.1017/S1431927620024721Metadata
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