Researchers at Georgia Tech have developed a prototype nanometer-scale generator that produces continuous direct-current electricity by harvesting mechanical energy from such environmental sources as ultrasonic waves, mechanical vibration or blood flow. Based on arrays of vertically-aligned zinc oxide nanowires that move inside a novel “zig-zag” plate electrode, the nanogenerators could provide a new way to power nanoscale devices without batteries or other external power sources.
The nanogenerators take advantage of the unique coupled piezoelectric and semiconducting properties of zinc oxide nanostructures, which produce small electrical charges when they are flexed. Fabrication begins with growing an array of vertically-aligned nanowires approximately a half-micron apart on gallium arsenide, sapphire or a flexible polymer substrate. A layer of zinc oxide is grown on top of substrate to collect the current. The researchers also fabricate silicon “zig-zag” electrodes, which contain thousands of nanometer-scale tips made conductive by a platinum coating.
This device could be a big step forward for self-powered nanotech devices and could help bring about the future of nano-machines.