A semiconductor-free micro-electronic device based on metamaterials

Semiconductor-free microelectronic device handles high power

Image credit: Credit: UC San Diego Applied Electromagnetics Group

The first microelectronic device that doesn’t contain semiconductors but conducts electricity 1,000 times better than conventional electronic devices has been created by American researchers.

The device is made of metamaterials, specially engineered materials that can be activated when exposed to a low voltage of less than 10V and illuminated by a low-power infrared laser. This creates spots of high-intensity electric field on the surface of the metamaterial that release electrons into the space above.

The device, developed by engineers from the University of California San Diego, has been described in an article in the latest issue of the journal Nature Communications.

In experiments, the device was able to handle much more power than conventional semiconductors. The researchers believe the invention could pave the way for faster microelectronic devices and more efficient solar panels.

 

“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,” said engineering professor Dan Sievenpiper, who led the team.

Current microelectronic devices, such as transistors, are limited by the properties of the materials they are made of. The conductivity of semiconductor materials used in these devices is usually limited by what is known as band gap. That means they require a boost of external energy to get the electrons flowing. The speed of the electrons’ motion is also limited as they constantly collide with atoms in the semiconductor.

The solution by the San Diego team removes these limitations. As the electrons float freely above the metamaterial surface, they don’t face any obstacles

“Next we need to understand how far these devices can be scaled and the limits of their performance,” Sievenpiper said.

The proof-of-concept metamaterial consists of an array of gold mushroom-like nanostructures on an array of parallel gold strips. This structure is positioned on top of a silicon wafer with a layer of silicon dioxide in between.

The researchers said different metasurfaces will need to be designed and optimised for different types of applications.

Previously, liberating electrons from materials has been extremely challenging. It would require applying extremely high voltages of at least 100V, the use of high-power lasers or temperature of more than 500°C. The device by the San Diego team requires none of these.

The team is also exploring other applications for this technology besides electronics, such as photochemistry, photocatalysis, enabling new kinds of photovoltaic devices or environmental applications.

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