海角大神

Scientists at the University of California San Diego have created the world's first microelectronic device that needs no semiconductors. Instead, this chip is made of metamaterials that can be activated by a weak laser pulse and low voltage.

The device, described last week in the journal Nature Communications, is 1,000 percent more conductive than a standard transistor. Using this new technology, scientists may someday be able to build faster and more powerful microelectronics such as solar panels.

鈥淭his certainly won鈥檛 replace all semiconductor devices, but it may be the best approach for certain specialty applications, such as very high frequencies or high power devices,鈥� co-author Dan Sievenpiper, a professor of electrical engineering at UCSD, said in a statement.

Since the 1950s, transistors have powered nearly every commercial electronic on the market. When powered by an electrical current, these little metalloid devices can switch between on and off states in a circuit and amplify electronic signals.

But these devices can only be as powerful as the materials that compose them. Transistors are made of semiconductors 鈥� that is, any solid more conductive than an insulator but less conductive than most metals. Semiconductive materials have a band gap, which means they need plenty of outside energy to start the flow of electrons. Those electrons collide with atoms as they race through the transistor, limiting their velocity and hindering the speed of the device.

There鈥檚 room for improvement, to be sure. In September, researchers from the University of Wisconsin-Madison developed the first carbon nanotube transistor to outperform the usual silicon variety.

海角大神鈥檚 Weston Williams reported:

But Dr. Sievenpiper鈥檚 device goes a step further, ditching the semiconductor altogether. Instead, researchers etched tiny nanostructures into an array of gold strips. They attached this metasurface to a silicon 鈥渨afer,鈥� and added a layer of silicon dioxide in between the two.

This metamaterial can be 鈥渆xcited鈥� by less than 10 volts of power and a low-energy infrared laser. That creates 鈥渉ot spots鈥� on the gold nanostructure, which in turn produce strong enough electrical fields to decouple electrons from the metastructure. The electrons can then move about freely.

The chip, of course, is only a proof-of-concept. To optimize performance for practical electronic devices, researchers will first need to design different metasurfaces.

鈥淣ext we need to understand how far these devices can be scaled and the limits of their performance,鈥� Sievenpiper said.