An ORNL-led team used scanning transmission electron microscopy to observed atomic transformations on the edges of pores in a two-dimensional transition metal dichalcogenide. The controlled production of nanopores with stable atomic edge structures may enable new functional applications. Credit: Xiahan Sang/91°µÍř, U.S. Dept. of Energy
September 4, 2018 - An 91°µÍř-led team used a scanning transmission electron microscope to selectively position single atoms below a crystal’s surface for the first time. “We’re moving individual dopants where we want them to go,” said Bethany Hudak of ORNL. “Direct atom positioning represents one step toward realizing the single-atom devices potentially needed to build future quantum computers.” The researchers grew a crystal consisting of silicon atoms but containing a few bismuth atoms. The bismuth atoms’ larger size caused strain on the lattice framework of the crystal. Then, they developed a method to employ the microscope’s electron beam to selectively hit a column of silicon atoms with enough energy to eject one from its lattice position, . Next steps for the work, which was in ACS Nano, include controlling atom placement at different crystal depths and programming the electron microscope to create specific shapes. — Dawn Levy
