What can you do with a nano-sized soldering iron? William King has a few ideas.
As a graduate student, King was invited to join the Millipede project at IBM’s Zürich Laboratory. The project’s experimental data storage device uses a cantilevered silicon bar with a tip just 20 nanometers wide to melt tiny divots into plastic, “writing” data at 50 times the density of today’s best hard drives.
By modeling the choppy flow of heat through the narrow silicon bars, King helped IBM engineers control it precisely–and so use a single tip to read, write, and even erase data. Since joining the Georgia Tech faculty in 2002, King has incorporated similar tips into nano soldering irons for making items as diverse as electronic circuits and tissue-engineering scaffolds. By cycling the tips to 1,200 °C and back to room temperature millions of times a second, King releases the “solder”–be it a semiconductor, an insulator, or a biocompatible polymer–far more precisely and quickly than researchers who deposit materials by lowering and raising silicon tips.