Scientists at the Department of Energy”s Oak Ridge National Laboratory are the first to harness a scanning transmission electron microscope (STEM) to directly write tiny patterns in metallic “ink,” forming features in liquid that are finer than half the width of a human hair.
The automated process is controlled y weaving a STEM instrument”s electron beam through a liquid-filled cell to spur deposition of metal onto a silicon microchip. The patterns created are “nanoscale,” or on the size scale of atoms or molecules.
Usually fabrication of nanoscale patterns requires lithography, which employs masks to prevent material from accumulating on protected areas. ORNL”s new direct-write technology is like lithography without the mask.
Details of the unique capability are published online in Nanoscale, a journal of the Royal Society of Chemistry, and researchers are applying for a patent. The technique may provide a new way to tailor devices for electronics and other applications.
“We can now deposit high-purity metals at specific sites to build structures, with tailored material properties for a specific application,” said lead author Raymond Unocic of the Center for Nanophase Materials Sciences (CNMS), a DOE Office of Science User Facility at ORNL. “We can customize architectures and chemistries. We”re only limited by systems that are dissolvable in the liquid and can undergo chemical reactions.”