EPFL researchers have come up with a new approach to electronics that involves manipulating metastructures on the subwavelength scale. Applications such as 6G communications could be used to launch the next generation of ultra-fast devices for exchanging large amounts of data.
Until now, the ability to make electronic devices faster has come down to the simple principle of shrinking transistors and other components. However, this approach has reached its limits. This is because the benefits of miniaturization are offset by detrimental effects such as reduced resistance and output power.
Therefore, further miniaturization is not a viable solution for better electronics performance, explains Elison Matioli of the Power and Wide-Bandgap Electronics Laboratory (POWERlab) at EPFL’s Faculty of Engineering. “There are new papers coming out describing smaller and smaller devices, but for materials made of gallium nitride, the best devices in terms of frequency have already been published several years ago,” he says. “Then, as devices shrink in size, they face fundamental limitations, so it doesn’t get any better. This is true regardless of the materials used.”
In response to this challenge, Matioli and PhD student Mohammad Samizadeh Nikoo came up with a new approach to electronics that overcomes these limitations and enables a new class of terahertz devices. Instead of shrinking the device, they rearranged it. In particular, this was done by etching patterned contacts, called metastructures, at sub-wavelength distances on semiconductors made of gallium nitride and indium gallium nitride. These metastructures allow us to control the electric field within the device, giving us extraordinary properties that do not occur in nature.
Importantly, the device can operate at electromagnetic frequencies in the terahertz range (0.3 to 30 THz). This is much faster than the gigahertz waves used in today’s electronic devices. Therefore, much more information can be transmitted in a given signal or period, offering great potential for applications in 6G communication and beyond.
“We have found that manipulating radio frequency fields at the microscale can significantly improve the performance of electronic devices without resorting to aggressive downscaling,” Blake recently published in Nature. Samizadeh Nikoo, lead author of the Thru article, explains:
Records high frequencies, records low resistance
This range is often referred to as the “terahertz gap” because terahertz frequencies are too fast to be managed by modern electronics and too slow for optical applications. Modulating terahertz waves using sub-wavelength metastructures is a technique that originated in the world of optics. However, POWERlab’s method allows an unprecedented level of electronic control, unlike optical approaches that illuminate existing patterns with an external light beam.
“In our electronics-based approach, the ability to control induced radio frequencies comes from a combination of sub-wavelength patterned contacts and control of electronic channels by applied voltages. By doing (or not inducing), it means that we can change collective effects in metadevices,” says Matioli.
While most state-of-the-art devices on the market today can achieve frequencies up to 2 THz, POWERlab’s metadevices can reach 20 THz. Similarly, today’s devices operating near the terahertz range tend to fail at voltages below 2 volts, while metadevices can support 20 volts or more. This will enable the transmission and modulation of terahertz signals at much greater powers and frequencies than is currently possible.
Integrated solution
As Samizadeh Nikoo explains, the increasing data requirements of technologies such as self-driving cars and 6G mobile communications are rapidly pushing the limits of today’s devices, so modulation of terahertz waves is the future of telecommunications. It is important. Electronic metadevices developed at POWERlab could form the basis for integrated terahertz electronics, for example by producing compact high-frequency chips already used in smartphones.
“This new technology has the potential to change the future of ultra-high-speed communications because it is compatible with existing processes in semiconductor manufacturing. 10 times faster than 5G,” says Samizadeh Nikoo.
The next step in realizing the full potential of this approach is to develop other electronic components that are ready to be integrated into terahertz circuits, says Mattioli.
“Integrated terahertz electronics is the next frontier of the connected future. But our electronic metadevices are just one component. We need to develop terahertz components, that is our vision and goal.”
Original: Electronic Metadevices Break Barriers to Ultrafast Communication
Than: Lausanne Federal Institute of Technology
