Excitons to Take Electronics into the Future

Ecole Polytechnique Fédérale de Lausanne (EPFL) researchers have developed a transistor based on excitons – a type of particle most people have not heard of – that is able to function at room temperature. This breakthrough could lead to a new breed of faster, more energy efficient and smaller electronics. The study was published this week in Nature

Excitons could revolutionize the way engineers approach electronics. A team of EPFL researchers has created a new type of transistor – one of the components of circuits – using these particles instead of electrons. What is remarkable is that their exciton-based transistor functions effectively at room temperature, a hitherto insurmountable obstacle. They achieved this by using two 2D materials as semiconductors. Their study, which was published today in Nature, has numerous implications in the field of excitonics, one of the most promising new areas of study alongside photonics and spintronics.

“Our research showed that, by manipulating excitons, we had come upon a whole new approach to electronics,” says Andras Kis, who heads EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES). “We are witnessing the emergence of a totally new field of study, the full scope of which we don’t yet know.”

This breakthrough sets the stage for optoelectronic devices that consume less energy and are both smaller and faster than current devices. In addition, it will be possible to integrate optical transmission and electronic data-processing systems into the same device, which will reduce the number of operations needed and make the systems more efficient.

Higher energy level

Excitons are actually quasiparticles, a term used to describe the interaction between the particles that make up a given substance rather than the substance itself. Excitons consist of an electron and an electron hole. The two are bound together when the electron absorbs a photon and achieves a higher level of energy; the “excited” electron leaves behind a hole in the previous level of energy, which, in band theory, is called a valence band. This hole, also a quasiparticle, is an indication of the missing electron in this band.