Phase transformation of Sn-based nanowires under electron beam irradiation†
One dimensional metal phase change nanomaterials provide a valuable research platform for understanding nanoscale phase transformation behavior and thermal properties, which have potential applications in identification systems such as information storage, barcoding, and detection. Tin(Sn)-based nanowires fabricated using a direct current electrodeposition technique into nanoporous templates are irradiated using electron beam (e-beam) in situ transmission electron microscopy. With the assistance of an oxide shell covering on the Sn-based nanowires, periodic and non-periodic multi-layered nanostructures are precisely sculpted and the reversibility between the original homogeneous alloy phase and the precipitated phases is controllable. The formation mechanism of the phase reversibility and sculpting process also works on other phase change materials, and this was proved using individual SnPb alloy nanowires as a test material. A single Sn–Ag alloy nanowire several microns in length was proved to be easily coded into dozens of morphology/phase statuses, which can be used to produce more than 1000 barcodes. This controllable, phase tunable strategy via selective e-beam irradiation engineering technique is believed to open up a way of sculpting an individual nanowire with various phase statuses and periodicities, which it may be possible to encode into a promising micro–nano identification system with the advantages of ultrahigh capacity, sustainable utilization and good stability.