Researchers from the Cockrell School of Engineering at the University of Texas, Austin, have developed ‘bubble-pen lithography,’ a device that can efficiently handle nanoparticles.
The new method relies on microbubbles to inscribe or write on the surface of nanoparticles like tiny pieces of gold, silicon and other materials.
Researchers’ interest in nanoparticles – between the size of 1 and 100 nanometers – has grown rapidly because of their versatility and strength. But working with these particles while keeping their properties and functions intact is difficult. The existing lithography methods are not capable of fixing nanoparticles to a specific location with precise and arbitrary control.
The research team led by Texas Engineering assistant professor Yuebing Zheng has invented a method to handle these small particles and lock them into position without damaging them. Using microbubbles to gently transport the particles, the bubble-pen lithography technique can quickly arrange particles in various shapes, sizes, compositions and distances between nanostructures.
By means of their bubble-pen device, the researchers focused a laser underneath a sheet of gold ‘nanoislands’ to generate a hotspot that creates a microbubble out of vaporized water. The bubble attracts and captures a nanoparticle through a combination of gas pressure, thermal and surface tension, surface adhesion and convection.
The laser then steers the microbubble to move a nanoparticle on the surface and disappears when the laser is turned off, leaving the particles intact.
“The ability to control a single nanoparticle and fix it to a substrate without damaging it could open up great opportunities for the creation of new materials and devices,” said Zheng. “The capability of arranging the particles will help to advance a class of new materials, known as metamaterials, with properties and functions that do not exist in current natural materials.”
Image credits: Cockrell School of Engineering