EPFL scientists have developed a new approach to electronics involving engineering metastructures at the sub-wavelength scale. For exchanging huge amounts of data, with applications in 6G communications and more, it could launch the next generation of ultra-fast devices.
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The drive to make electronic devices better has come down to a simple principle: scaling down transistors and other components. However, this method is reaching its limit, as the advantages of shrinking are accomapnied by disadvantages like resistance and reduced power output.
Elison Matioli of the Power and Wide-band-gap Electronics Research Lab (POWERlab) in EPFL’s School of Engineering says that more miniaturization is not a feasible solution to improved electronics performance.
New papers come out describing smaller and smaller devices, but in the case of materials made from gallium nitride, the best devices in terms of frequency were already published a few years back. After that, there is really nothing better, because as device size is reduced, we face fundamental limitations. This is true regardless of the material used.
Elison Matioli, POWERlab, School of Engineering, École polytechnique fédérale de Lausanne
As a solution to this challenge, Matioli and Ph.D. student Mohammad Samizadeh Nikoo developed a new approach to electronics that can win over these restrictions and facilitate a new class of terahertz devices.
Rather than shrinking their device, they rearranged it by etching patterned contacts known as metastructures onto a semiconductor composed of gallium nitride and indium gallium nitride at sub-wavelength distances. These metastructures enable the electrical fields within the device to be regulated, which exhibit extraordinary features that do not happen in nature.
Significantly, the device can function at electromagnetic frequencies in the terahertz range (between 0.3–30 THz)—considerably quicker than the gigahertz waves employed in present day’s electronics. Therefore, they can carry much larger quantities of data for a given period or signal, which offer them great possibility for applications in 6G communications and beyond.
We found that manipulating radiofrequency fields at microscopic scales can significantly boost the performance of electronic devices, without relying on aggressive downscaling.
Samizadeh Nikoo, Study First Author, École polytechnique fédérale de Lausanne
This discovery was recently published in the journal Nature.
Record High Frequencies, Record Low Resistance
As terahertz frequencies are too slow for optics applications to manage, and too quick for current electronics, the range is usually called the “terahertz gap.” Employing sub-wavelength metastructures to modulate terahertz waves is an approach that comes from the optics world. However, the method of POWERlab enables for an extraordinary degree of electronic control, contrary to the optics technique of shining an external beam of light onto an existing pattern.
In our electronics-based approach, the ability to control induced radiofrequencies comes from the combination of the sub-wavelength patterned contacts, plus the control of the electronic channel with applied voltage. This means that we can change the collective effect inside the metadevice by inducing electrons (or not).
Elison Matioli, POWERlab, School of Engineering, École polytechnique fédérale de Lausanne
Although the most cutting-edge devices on the market currently can attain frequencies of up to 2 THz, the metadevices of POWERlab can achieve 20 THz. Likewise, today’s devices functioning near the terahertz range break down less than 2 volts, whereas the metadevices can support more than 20 volts. This allows the modulation and transmission of terahertz signals with much greater frequency and power than is possible at present.
Integrated Solutions
As Samizadeh Nikoo describes, modulating terahertz waves is important for the telecommunications’ future, as the growing data needs of technologies such as autonomous vehicles and 6G mobile communications are quick reaching the limits of today’s devices.
The electronic metadevices built in the POWERlab can form the foundation for integrated terahertz electronics by building compact, high-frequency chips that could already be operated with smartphones, for instance.
“This new technology could change the future of ultra-high-speed communications, as it is compatible with existing processes in semiconductor manufacturing. We have demonstrated data transmission of up to 100 gigabits per second at terahertz frequencies, which is already 10 times higher than what we have today with 5G,” Samizadeh Nikoo states.
Matioli states that the next step is to come with other electronics components that are ready for integration into terahertz circuits to completely understand the capacity of the technique.
“Integrated terahertz electronics are the next frontier for a connected future. But our electronic metadevices are just one component. We need to develop other integrated terahertz components to fully realize the potential of this technology. That is our vision and goal,” he concludes.
Journal Reference
Samizadeh Nikoo, M., and Matioli, E. (2023) Electronic metadevices for terahertz applications. Nature. doi.org/10.1038/s41586-022-05595-z.
Source: https://actu.epfl.ch/