title: Rapid measurement of nanoparticle thickness profiles.
abstract: A method to measure the thickness of a single-crystal nanoparticle in the direction parallel to the incident beam from annular dark field scanning transmission electron microscope (ADF-STEM) images is reported, providing a map of thickness versus position across the nanoparticle--a 'thickness profile' image. The method is rapid and hence suitable for surveying large numbers of nanoparticles. The method measures the intensity scattered to a characterised ADF detector and compares this to the incident beam intensity, to obtain a normalized ADF image. The normalised intensity is then converted to thickness via dynamical ADF image simulations. The method is accurate within 10% and the precision is dominated primarily by 'shot noise'. Merits and limitations of this method are discussed. A method to calibrate the response function of the ADF detector without external equipment is also described, which is applicable to the entire range of gain and background settings.
authors.affiliation: Department of Materials Engineering, Monash University, VIC 3800, Australia. hadas.katz@monash.edu
authors.forename: Hadas
authors.initials: H
authors.lastname: Katz-Boon
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Rossouw
authors.forename: Christian
authors.initials: C
authors.lastname: Dwyer
authors.forename: Joanne
authors.initials: J
authors.lastname: Etheridge
mesh_terms: D017348:Microscopy, Electron, Scanning Transmission / Q000295:instrumentation* / Q000379:methods*; D053758:Nanoparticles / Q000648:ultrastructure*