Edge-melting: nanoscale key-mechanism to explain nanoparticle formation from heated TEM grids

Abstract

In this study, we examine at both experimental and fundamental levels, the experimental evidence of nanoparticle formation in transmission electron microscopy (TEM) metal grids annealed at temperatures lower than the melting point of the corresponding metal bulk material. Our experimental investigation considers the most thermally unstable TEM grids (i.e. Cu-grids) and inspects the possible sources and mechanisms of contamination of thin films, conventionally deposited on carbon-coated Cu-grids. The investigations are supported by morphological-compositional analyses performed in different regions of the TEM sample. Then, a general model is formulated and discussed in order to explain the grid thermal instability, based on the critical role of edge-melting (i.e. melting initiated at edges and corners of the grid bars), the enhanced rate of evaporation from a liquid surface and the polycristallinity of the grid bars. Hence, we totally disregard conventional arguments such as bulk evaporation and metal vapor pressure and, in order to emphasize and clarify the alternative point of view of our model, we also overview the nano-scale melting phenomenology relevant to our discussion and survey the discrepancies reported in the literature. (C) 2016 Elsevier B.V. All rights reserved.


Autore Pugliese

Tutti gli autori

  • Cesaria M.; Taurino A.; Catalano M.; Caricato A.P.; Martino M.

Titolo volume/Rivista

Applied surface science


Anno di pubblicazione

2016

ISSN

0169-4332

ISBN

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Nessuna citazione

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