Using the concept of quantum tunneling, researchers developed a diode that harvests infrared heat and turns it into electricity.
Researchers have come up with a way we could harvest energy from Earth by turning excess infrared radiation and waste heat into electricity we can use. Our planet absorbs massive amounts of sunlight which in turn leads to a near-constant emission of infrared radiation, which is estimated to amount to millions of gigawatts of energy.
The concept involves the strange physics of quantum tunneling, and the key to the idea is a specially designed antenna that can detect waste or infrared heat as high-frequency electromagnetic waves, transforming these quadrillionth-of-a-second wave signals into a direct charge.
There’s actually a lot of energy going to waste here on Earth – most sunlight that hits the planet gets sucked up by surfaces, the oceans, and our atmosphere.
This warming leads to a constant leak of infrared radiation that some estimate to be as much as millions of gigawatts
Because the infrared wavelengths are so short, to harness them we need super-tiny antennas. According to the international team of researchers behind the new study, it’s quantum tunneling that could provide the breakthrough required.
“There is no commercial diode in the world that can operate at such high frequency,” says lead researcher Atif Shamim from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. “That’s why we turned to quantum tunneling.”Quantum tunneling is a well-established phenomenon in quantum physics where a particle can get through a barrier without having enough energy to do so.
One of the examples used most often is of a ball rolling up a hill: in classical physics, the ball needs a certain amount of energy behind it to get up the hill and over to the other side.
But in quantum physics, the ball can tunnel through the hill with less energy, thanks to the positional uncertainty that’s at the heart of everything quantum.
How does this help in the construction of nanoscale antennas? It enables electrons to be moved through a small barrier, via a tunneling device like a metal-insulator-metal (MIM) diode, turning infrared waves into current along the way.
The scientists were able to create a new bowtie-shaped nanoantenna, sandwiching the thin insulator film between two slightly overlapped metallic arms made from gold and titanium, giving them a device capable of generating the intense electrical fields required for 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.
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.”
The research has been published in Materials Today Energy.
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