Removal of supporting amorphous carbon film induced artefact from measured strain variation within a nanoparticle

Abstract

Strain variation within nanoparticles plays a crucial role in defining important properties related to their applications. Transmission electron microscopy (TEM) based imaging techniques are mostly used to determine strain variation within nanoparticle and supporting amorphous carbon film induced artefact in measured strain variation. In this present work, an algorithm is reported which is capable of removing supporting film induced artefacts from measured strain variations within nanoparticles. The effectivity of the algorithm was tested using simulated TEM results which proves that the algorithm works satisfactorily down to t_p/t_AC ratio of 0.25, where t_p and t_AC defines the thicknesses along the electron beam of nanoparticle and supporting amorphous film respectively. These simulations also reveal that changing the atomic number of atoms within the nanoparticle, or the density of the amorphous carbon does not affect the algorithm's effectiveness. When the algorithm was applied on experimental TEM results of a TiO₂ nanoparticle, it even worked well for t_p/t_AC below 0.25, i.e. a relatively thick layer of amorphous carbon.

Keywords: Geometric phase analysis; Nanoparticle; Strain artefact; Supporting amorphous carbon film; Transmission electron microscopy.