Nano-Generator Could Power Tiny Devices

The day when you can charge your cell phone or iPod just by going for a stroll around the block could be a step closer, thanks to a nano-generator. About a year ago, Zhong Lin Wang of Georgia Tech in the US discovered that, when he disturbed zinc oxide nanowires, they gave off a tiny electrical current, a phenomenon called piezoelectricity. At the time, he had to use the tip of an atomic force microscope — a $250,000 instrument — to create about one-billionth of a watt of power. Not exactly energy efficiency. But with his latest experiment, Wang has improved his design at least a thousand-fold