Using the concept of quantum tunneling, researchers developed a diode that harvests infrared heat and turns it into electricity.

A team of researchers from the King Abdullah University of Science and Technology in Saudi Arabia reportedly created a device that could generate power from infrared radiation and other waste heat. The device was allegedly built using the concept of quantum tunneling which enables it to transform “quadrillionth-of-a-second wave signals” into a direct charge.

In Physics, tunneling is said to be the quantum mechanical effect of an object transitioning through a so-called barrier that it “classically” could not surmount. For instance, it is possible to roll a ball “up” or “over the hill” provided that the ball has been given enough force or energy. Classically, this concept makes sense.

Quantum Tunelling effect
Quantum Tunneling effect | Wikimedia Commons | commons.wikimedia.org

However, that concept is not applicable in quantum mechanics since objects in this state do not behave like classical objects. Instead, on a quantum scale, objects exhibit wavelike behavior. Meaning, the wave function describing a quantum particle moving towards a hill can extend to the other side of it.

Unlike a ball (classical object) that will stop or roll back down the hill when not given enough velocity, a quantum particle can tunnel through the barrier even when it doesn’t have sufficient energy to surmount it. This is because, in quantum mechanics, the particle can borrow energy from its surroundings to go through a barrier.

Researchers from the King Abdullah University of Science and Technology developed a device that uses #Quantum tunnelling to harvest infrared radiation and turn it into useful electricity.Click To Tweet

Quantum Tunnelling Device

The wavelengths of infrared radiation are very short. Super tiny antennas that can operate at high frequencies are needed to harness them. Unfortunately, no diode in the world can do that, so, the researchers turned to quantum tunneling.

“There is no commercial diode in the world that can operate at such high frequency,” Atif Shamim, project leader from KAUST, was quoted as saying. “That’s why we turned to quantum tunneling.”

Quantum Tunnelling through a barrier
Quantum tunneling through a barrier. At the origin (x=0), if there is a very high but narrow potential barrier. A significant tunneling effect can be seen | Wikipedia | Wikipedia.org

The researchers, instead, created nanoscale antennas. These can move electrons through a small barrier using a metal-insulator-metal (MIM) diode which acts as a tunneling device.

The device has a bowtie-shaped nanoantenna that secures a thin insulator film between two slightly overlapping metallic arms made of gold and titanium. This design enables it to generate intense electrical fields required for the tunneling to work.

“The most challenging part was the nanoscale overlap of the two antenna arms, which required very precise alignment,” one of the researchers, Gaurav Jayaswal, said. “Nonetheless, by combining clever tricks with the advanced tools at KAUST’s nanofabrication facility we accomplished this step.”

Apparently, the MIM diode developed by the researchers can successfully capture infrared radiation with zero applied voltage. Meaning, it only turns on when needed.

Infrared energy diode used in the quantum tunnelling device
Infrared energy diode used in the quantum tunneling device | Atif Shamim | discovery.kaust.edu.sa

Potential Application of the Quantum Tunneling Device

Earth has an abundant supply of heat, and most of it is only being absorbed by surfaces, oceans, and the atmosphere. Because of this, infrared radiation is constantly being emitted around us. To date, solar panels can only harvest heat energy during daylight and when the weather permits it.

However, the quantum tunneling device by the KAUST researchers could be a major game changer as it can tap into both heat and infrared radiation energy. Aside from that, it can also harvest infrared radiation and other waste heat energy non-stop for 24 hours.

“This is just the beginning – a proof of concept,” Shamim said. “We could have millions of such devices connected to boost overall electricity generation.”

Aside from harvesting untapped energy sources on our planet, where else do you think can quantum tunneling be used?

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