Computers That Do Windows

Don’t be surprised if your computer pulls a disappearing act one day. Research groups in the United States and Japan this year independently fabricated prototype transistors that are completely transparent. If the kinks can be worked out, the researchers say, the devices will change the way you think about computing. Transparent electronics could enable see-through displays-like video ads on store windows, or warning flashes on your windshield if a child darts in front of your car-and even invisible processors.

The new transistors are made from oxide semiconductors, such as zinc oxide, which are currently used in conductive coatings for touch screens and windshield defrosters. Until now, oxide-based devices have not had good enough electrical properties-the ability to handle large currents, say-to make practical transistors. Recent advances have improved techniques for alternating layers of the oxide with other chemical layers on glass and plastic. The result: transparent transistors that switch electric currents on and off fast enough to make integrated circuits.

It will be years before these transistors compete with silicon on a large scale. But one application is only two years away: brighter and more efficient liquid-crystal displays, a $10 billion market. Most of today’s laptop screens use opaque silicon transistors to control their pixels. The problem is that the silicon blocks much of the backlight, making screens dim and hard to read. Transparent electronics would yield brighter displays that use less power.

To make entire computers see-through will require faster and more stable transistors-and more efficient ways to pattern complex circuits. And see-through displays will require the development of transparent light-emitting devices. But eventually, says electrical engineer John Wager at Oregon State University, “anywhere there’s glass, there can be electronics.”