We are an interdisciplinary team using advanced electron and ion beam microscopy to characterize and manipulate matter down to the atomic scale.
Electron microscopes are traditionally employed for imaging, while ion microscopes are used for material shaping by sputtering. We challenge these conventions, leveraging scanning transmission electron microscopy (STEM) not only for atom-resolution imaging, but also for precise atomic rearrangement. Likewise, we explore focused ion beam (FIB) microscopy for novel imaging modalities alongside its application in material modification.
Our work advances fundamental materials understanding and drives the development of prototype devices for emerging applications.
We are grateful to the National Science Foundation for funding.
High-resolution TEM image showing triangular nanopores in monolayer hexagonal boron nitride fabricated using a combined ion and electron irradiation technique.
Image credit: Dana Byrne, UC Berkeley.
Byrne DO, Ciston J, Allen FI. Probing Defectivity Beneath the Hydrocarbon Blanket in 2D hBN Using TEM-EELS, Microscopy and Microanalysis 30(4):650 (2024) doi:10.1093/mam/ozae064
(Left) Helium ion micrograph of a butterfly wing scale with cross-section milled by Ga-FIB.
(Right) Higher magnification view showing lamina (L), ridges (R), and crossribs (r). The thickness of the lamina determines the color of the butterfly wing scale (structural color effect).
Image credits: Rachel Thayer and Frances Allen (UC Berkeley).
Thayer RC, Allen FI, Patel NH. Structural color in Junonia butterflies evolves by tuning scale lamina thickness, Elife 9:e52187 (2020) doi:10.7554/eLife.52187
(Top) Nanopillar with tip radius <10nm fabricated by He-FIB-induced deposition from a tungsten precursor onto a specialized AFM microcantilever.
(Bottom) Single frame from a movie of DNA in liquid scanned using our custom AFM tip.
Image credits: Frances Allen and Bibiana Onoa (UC Berkeley).
Allen FI, De Teresa JM, Onoa B. Focused Helium Ion and Electron Beam-Induced Deposition of Organometallic Tips for Dynamic Atomic Force Microscopy of Biomolecules in Liquid, ACS Applied Materials and Interfaces 16(4):4439 (2024) doi:10.1021/acsami.3c16407