Energy harvester generates continuous nanoampere current

Researchers at the Georgia Institute of Technology have created a tiny device that produces a direct current by harnessing the piezoelectric output of hundreds of swaying zinc-oxide nanowires. The device features a forest of vertically oriented nanowires, whose tips lie in the valleys of a peak-and-valley-shaped electrode. Buffeted by ultrasonic waves or mechanical vibration, the wires flex, periodically contacting an electrode and transferring their electrical charge. A prototype device produces current in the nanoampere range, but the researchers claim the technology can scale to produce 4W/cm³.