Control and Modification of Nanostructured Materials by Electron Beam Irradiation

• Main Author: Shun-Ichiro Tanaka
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Quantum Beam Science
• Subjects: electron irradiation; excited reaction field; transmission electron microscope; nanomaterials; manipulation; nanostructure
• Online Access: https://www.mdpi.com/2412-382X/5/3/23

I have proposed a bottom-up technology utilising irradiation with active beams, such as electrons and ions, to achieve nanostructures with a size of 3–40 nm. This can be used as a nanotechnology that provides the desired structures, materials, and phases at desired positions. Electron beam irradiation of metastable θ-Al₂O₃, more than 10¹⁹ e/cm²s in a transmission electron microscope (TEM), enables the production of oxide-free Al nanoparticles, which can be manipulated to undergo migration, bonding, rotation, revolution, and embedding. The manipulations are facilitated by momentum transfer from electrons to nanoparticles, which takes advantage of the spiral trajectory of the electron beam in the magnetic field of the TEM pole piece. Furthermore, onion-like fullerenes and intercalated structures on amorphous carbon films are induced through catalytic reactions. δ-, θ-Al₂O₃ ball/wire hybrid nanostructures were obtained in a short time using an electron irradiation flashing mode that switches between 10¹⁹ and 10²² e/cm²s. Various α-Al₂O₃ nanostructures, such as encapsulated nanoballs or nanorods, are also produced. In addition, the preparation or control of Pt, W, and Cu nanoparticles can be achieved by electron beam irradiation with a higher intensity.