In a monumental stride toward the future of computing, scientists have unveiled a breakthrough that could catapult computer processing speeds to previously unimaginable heights—operating in the petahertz regime, a thousand times faster than today’s fastest chips. This pioneering research, led by an international team including physicists and optical scientists from the University of Arizona, leverages ultrafast pulses of light to manipulate electrons in graphene, achieving electron dynamics that reimagine the ultimate speed limits of electronic devices.
At the heart of this innovation lies graphene, a two-dimensional lattice of carbon atoms known for its exceptional electrical, thermal, and mechanical properties. The researchers explored the electrical conductivity of custom-engineered graphene samples, with a focus on how electrons respond when excited by laser pulses lasting less than a trillionth of a second—specifically, pulses as fleeting as 638 attoseconds (an attosecond is a quintillionth of a second). These ultrashort laser bursts generate energy waves capable of moving electrons so rapidly that they seem to bypass traditional physical constraints.
Central to their experimental achievement is the exploitation of the quantum phenomenon known as tunneling. Unlike classical transport, where electrons must surmount energy barriers, tunneling allows them to effectively "pass through" barriers instantaneously, a behavior that defies conventional expectations. In this study, graphene’s symmetrical atomic arrangement initially produced balanced, opposing currents that canceled each other out under laser excitation. However, by introducing a specialized silicon layer and carefully modifying the graphene transistor, the team induced asymmetric electron flow, permitting them to observe and capture the elusive tunneling current in real time.
Harnessing a commercially available graphene phototransistor, the researchers transformed it into what they describe as the world’s fastest petahertz quantum transistor. This device functions as an ultrafast electronic switch powered by light rather than traditional electronic signals. Its operation hinges on the light-induced quantum tunneling currents, which allowed electrons to jump across potential barriers at speeds that reach the petahertz spectrum—equating to quadrillions of cycles per second. Such an astounding rate heralds a new era for ultrafast electronics, potentially revolutionizing how information is processed, transmitted, and controlled.
Mohammed Hassan, associate professor of physics and optical sciences and lead researcher in this project, highlights the paradigm shift this technology could herald. He underscores the disparity between explosive advances in artificial intelligence software and the comparatively languid pace of hardware development. By integrating quantum principles derived from cutting-edge quantum computing research, this petahertz transistor exemplifies the kind of hardware innovation that can bridge this gap, facilitating breakthroughs across scientific domains including space exploration, chemical analysis, and biomedical diagnostics.
The experiment’s success represents not only a scientific marvel but also a viable technological platform since the device operates under ambient conditions. Unlike many quantum phenomena that demand ultra-sophisticated, low-temperature environments, this transistor’s functionality in room temperature and standard atmospheric pressure conditions markedly eases the path toward real-world applications and mass production. Such practicality could accelerate commercialization efforts and spur new markets centered on petahertz-speed electronics.
Behind this advancement is a collaboration among faculty and students at the University of Arizona, notably researchers like Nikolay Golubev, Jalil Shah, Mohamed Sennary, and Mingrui Yuan, alongside scientists from the Jet Propulsion Laboratory at Caltech and Ludwig Maximilian University of Munich. Their multidisciplinary synergy brought expertise in optics, physics, and materials science to tackle the technical challenges inherent in capturing and controlling electron dynamics at attosecond timescales.
Technically, the team’s methodology focused on adapting the graphene phototransistor by embedding a silicon layer to create structural asymmetry. When irradiated with the highly controlled laser pulses, this configuration enabled the generation of non-canceling electron currents via quantum tunneling. Imaging analysis and temporally precise measurements revealed that electrons effectively leap across the potential barrier within the graphene framework, a phenomenon that, up until now, was theorized but never recorded at these speed scales with such clarity.
The implications extend far beyond incremental tech improvements. The integration of light-driven, quantum tunneling transistors into electronic circuits could unlock fundamentally new architectures in computing, with transistor switching times millions of times faster than current silicon-based devices. This catapult could energize quantum information science by providing new hardware platforms capable of managing the tremendous data flows required for quantum processors and complex simulations.
One of the most exciting prospects is the enhancement of computational power aiding advances in artificial intelligence. Ultrafast transistors leveraging petahertz speeds will be capable of feeding AI algorithms with data at unprecedented rates, shortening training times and refining decision-making processes. This breakthrough could also spur innovations in fundamental science, accelerating research that depends on real-time data analysis, such as experiments in particle physics, molecular interactions, and astrophysical observations.
Moreover, the successful demonstration of a light-induced petahertz transistor acquaints us with a future where electronic and photonic devices converge. Optical computing has long been hailed as the next frontier, aiming to overcome electrical resistance and thermal bottlenecks inherent to electron transport. By controlling electron flow with rapid light pulses, this research bridges the gap between photonics and electronics, paving the way for hybrid devices that capitalize on the speed and efficiency of photons while retaining the versatility of electronic components.
Currently, the team is working to integrate their discovery with commercially accessible equipment, striving to develop petahertz-speed transistors that can be manufactured at scale. With support from entities such as Tech Launch Arizona, these efforts involve refining device architecture to be compatible with existing microchip fabrication techniques and collaborating with industry stakeholders to transition this technology from laboratory curiosity to everyday reality.
This groundbreaking study, published in Nature Communications, marks a milestone in the ongoing quest to revolutionize the speed capacities of transistors. By harnessing the peculiarities of quantum mechanics with a practical, scalable device, researchers have charted a course toward the ultrafast computers of tomorrow that will redefine computational boundaries and enable scientific and technological frontiers once thought unreachable.
Subject of Research: Not applicable
Article Title: Light-induced quantum tunnelling current in graphene
News Publication Date: 9-May-2025
Web References:
10.1038/s41467-025-59675-5
Image Credits: Mohammed Hassan
Keywords:
Electronics, Photonics, All optical transistors, Optical computing, Semiconductors, Single electron transistors, Laser physics, Computational science, Computer science, Quantum information, Quantum processors, Optoelectronics
