Sunday , January 24 2021

Exciton Transistors Could Create More Energy-Efficient Electronics

Last year, researchers at the École polytechnique fédérale de Lausanne (EPFL) in Switzerland developed a new type of transistor – one based on excitons, a special type of quasiparticle – which could be used in the future, making it faster, and more efficient. And now the same team has made another breakthrough by discovering new properties of excitons.

An exciton is a subatomic quasiparticle, meaning that it is not a particle itself, but rather an interaction between two particles. In the case of excitons, they are made of a bound pair of one electron and one electron hole. (An electron hole is a space in an atom, where there is no electron.) The electron and electron hole becomes linked together when the electron absorbs a photon which gives it a higher level of energy, and the energetic electron moves position and leaves behind an electron hole The electron is negatively charged and the hole that leaves behind is positively charged, so the two bond in a process called the Coulomb attraction and form a exciton.

The EPFL team developed a transistor which used excitons instead of electrons The advantage of this is that the exciton transistor can operate effectively at room temperature, while the traditional electron transistors always produce heat when they operate. As transistors are a key component of circuits, having them produced no additional heat potentially means a big increase in energy efficiency and no need for large and heavy heat sinks or other cooling in electronic devices.

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Visualization of exciton transistors which used to be used in the future LANES / EPFL

The latest breakthrough scientists have created in the properties of excitons. The valley is the maximum and minimum energies that a particle express, and the valleys of electrons used to be used. store information in a field known as "valleytronics" which could extend the ending of Moore's Law. In the case of excitons, these valleys can be used to code and process information on a minuscule scale.

"Linking many devices that incorporate this technology will give us a new way to process data," Andras Kis, Head of EPFL's Laboratory of Nanoscale Electronics and Structures, explained in a statement. "By changing the polarization of light in a given device, we can then select a specific valley in another device. That's like switching from 0 to 1 or 1 to 0, which is the fundamental binary logic used in computing. "

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