A team of scientists from the University of California-San Diego have just reported the development of the first microelectronic device in the world that does not require a semiconductor. Instead of this very important component, this new chip is made out of metamaterials that can actually be activated by a weak laser pulse and just a little bit of voltage.
As a matter of fact, this new, smaller device is 1,000 percent more conductive than the standard transistor. That means this is the birth of a new technology that could, one day, help us to build faster and more powerful microelectronics (like solar panels, for example).
Of course, we can’t just replace existing semiconductor devices with this new technology just yet.
“This certainly won’t replace all semiconductor devices, but it may be the best approach for certain specialty applications, such as very high frequencies or high power devices,” explains UCSD electrical engineering professor Dan Sievenpiper in a recent news release.
Semiconductors—as we know them—put up varying levels of resistance, and each of these levels will constrain the velocity of electrons. In addition, semiconductors also have relatively large band gaps that can require initial bolts of energy in order to trigger conductivity; hence the new metamaterial needing just a single laser pulse or shock of voltage.
Large electronic devices have much bigger semiconductor components. These require similarly massive jolts of energy or stronger laser pulses or even high temperatures that can reduce some of the loss of energy to keep electrons flowing more freely. Strategies like this, unfortunately, do not work with smaller components (because you can’t just heap on more materials, basically).
As such, the team of researchers bypassed this problem by, first, abandoning traditional semiconductor materials for metamaterials, which are empowered by a metasurface—with gold, mushroom-like nanostructures that have been etched onto gold strips—affixed to a silicon wafer and then buffered by a single layer of silicon dioxide.
With even the slightest introduction of energy, then—as little as 10 volts—from a low-powered infrared laser—the gold nanostructures in the metasurfae begin to generate “hot spots”. These are very intense electric fields that are actually strong enough to decouple electrons from the material. After that, the electrons are pulled away from the underlying material, at which point they are free to move around unrestricted.
With that, researchers are now describing the breakthrough in a new paper that has been published this week in the scientific journal Nature Communications.
Still, Sievenpipe concludes: “Next we need to understand how far these devices can be scaled and the limits of their performance.”