Researchers at Cornell Universityhave, in collaboration with the Polish Academy of Sciences, achieved a major breakthrough in semiconductor technology by developing the very first double-sided chip – also called a ‘dualtronic’ chip – that integrates both photonic and electronic devices on a single gallium nitride (GaN) -waffle.
This innovation could reduce device sizes, improve energy efficiency and reduce production costs.
The unique crystal structure of the GaN wafer is the key to its dual functionality. Each side of the wafer has different properties, similar to how the poles of a magnet differ. The team used the metal-polar (Ga-polar) side to create light-emitting diodes (LEDs) and the nitrogen-polar (N-polar) side to build high electron mobility transistors (HEMTs). By doing this, they were able to achieve a configuration where the HEMT on one side powers the LED on the other – a feat never before achieved in any semiconductor material.
Limited only by the imagination
The research, led by Cornell professors Debdeep Jena and Huili Grace Xing, along with co-lead authors Len van Deurzen and Eungkyun Kim, is published in the Nature magazine.
“To our knowledge, no one has made active devices on both sides, not even for silicon,” noted co-lead author Len van Deurzen, highlighting how this feat was only possible because of GaN’s polarity-dependent properties. Traditional silicon wafers are cube-shaped, making both sides nearly identical, which prevents such a design.
According to the researchers, this dualtronic approach could have direct applications in making microLED screens more affordable and energy efficient. By integrating photonic and electronic functions into a single chip, fewer components would be required, leading to lower production costs and a smaller device footprint. These advances could have a significant impact on display production, potentially making LED displays cheaper and more compact.
The technology’s potential goes even further. With the ability to use the same wafer for different functions, dualtronics could allow smartphone screens to be reused as antennas, supporting wireless communications directly through the display. The polarization properties of GaN and the multifunctionality of the dualtronic chip could transform not only displays, but also radio frequency devices, lasers and future 5G/6G technologies.
“A good analogy is the iPhone,” explains Debdeep Jena. “Of course it’s a phone, but there are so many other things. It is a calculator, it is a map, with which you can look on the Internet. So there’s a bit of a convergence aspect to it. I would say that our first demonstration of ‘dualtronics’ in this article is the convergence of perhaps two or three functionalities, but in reality it is bigger than that.”
This breakthrough could reshape the way semiconductor devices are designed and used. By eliminating the need for separate chips for different functions, dualtronics promises to optimize both performance and resource usage for a variety of technologies. As the researchers note, this development marks an important step forward, and the potential applications are “limited only by the imagination.”