How to 3D Print on the Nanoscale

Electron beam controllably builds micro- and nanoscale structures, enabling new three-dimensional materials.

Nanoscale
A 32-face 3D truncated icosahedron mesh was created to test a simulation’s ability to guide precise construction of complex geometries. Scanning electron microscopy of the product (left) showed excellent agreement with the nanoscale structure that the simulation predicted (right). Reprinted (adapted) with permission from Jason D. Fowlkes, Robert Winkler, Brett B. Lewis, Michael G. Stanford, Harald Plank, and Philip D. Rack, “Simulation Guided 3D Nanomanufacturing via Focused Electron Beam Induced Deposition.” ACS Nano 10, pp. 6163-6172 (2016). DOI: 10.1021/acsnano.6b02108. Copyright 2016 American Chemical Society.

The Science

Realization of “3D printing” material assembly on the micron or even nanometer scale has posed significant challenges to researchers. Now, scientists have developed a specialized computer simulation that guides an electron beam to create custom 3D structures. The beam induces a precursor material to deposit in a way that forms complex shapes. This nanoscale 3D printing creates freestanding structures so tiny that bacteria dwarf them.

The Impact

The new approach, simulation-guided material deposition at the nanoscale, offers a path to synthesize materials with superior mechanical and optical properties. This design approach replaces trial-and-error in nanomanufacturing for materials and structures with superior mechanical and optical properties.

Summary

Precision control of nanometer scale 3D fabrication has been a longstanding research goal. Now, researchers have developed a 3D simulation that guides focused electron beam induced deposition (FEBiD) of precursor molecules on a surface and accurately predicts the complex geometries of deposited shapes over the length scale from nanometers to micrometers. The simulation predicts gas-solid interactions where the electron beam strikes a surface. While FEBiD can direct-write freestanding 3D nanostructures, improved understanding of the dynamic interplay of the scanning electron beam and adsorbed precursor molecules is critical for advancing additive manufacturing of optoelectronics, metamaterials, and more. The simulations consist of (1) a Monte Carlo simulation to calculate the electron–solid interaction and (2) a continuum simulation to calculate surface adsorption, desorption, diffusion, and deposition of precursor molecules. The merged simulation can guide the electron beam to produce complex lattices and meshes sized between 10 nanometers and 1 micron.