Nanowire Growth by an Electron‐Beam‐Induced Massive Phase Transformation

Abstract

Tungsten trioxide nanowires of a high aspect ratio have been synthesized in situ in a TEM under an electron beam of current density 14 A/cm 2 due to a massive polymorphic reaction. Sol-gel-processed cubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one-dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. The findings are important to the controlled electron beam deposition of nanowires for functional applications starting from colloidal precursors.

Self-Supported Nano-WO3 Foams formed by Self-Assembly of Non-Woven Mats

“…The peaks obtained come from two phases and were matched to the cubic WO 3 (JCPDS 41-905) and a non-stoichiometric oxide of tungsten WO 2.9 (JCPDS 18-1417). Formation of cubic WO 3 has earlier been reported by our group when annealing the as-spun mats at these temperatures [11]. The formation of non-stoichiometric phase is attributed to an oxygen deficient environment occurring during polymer degradation upon heat-treatment.…”

In-situ Quasi-Instantaneous e-beam Driven Catalyst-Free Formation Of Crystalline Aluminum Borate Nanowires

“…This growth mechanism can also be extended to describe the formation of other nanowires, for example, WO 3 nanowires produced inside a TEM14 as well as other synthesis routes891011.…”

Polymorphic Biological and Inorganic Functional Nanomaterials

“…Novel processing of γ-WO 3 nanowires from metastable precursors under electron irradiation has produced polytypic nanowires in a rapid process ( Figure 7 ). The single-phase, one-dimensional structures show polytypism as manifested in the high-resolution TEM and the selected area diffraction pattern [ 33 ]. A soft lithography technique was demonstrated by other workers to pattern amorphous “generic amyloid inks”, consisting of CsGA proteins into well-defined arrays of β-sheet structures post-curing [ 5 ].…”

“… ( a ) TEM image of γ-WO 3 nanowires grown on silicon nitride grid [ 33 ]; ( b ) TEM image of γ-WO 3 nanowires grown on copper mesh grid [ 33 ]. …”