Breaking the Wall of Terahertz Electronics

Breaking the Wall of Terahertz Electronics

Global Call 2026 Finalist Interview: Engineering & Technology

Mohammad Nikoo is a Nanyang Assistant Professor in NTU’s School of Electrical and Electronic Engineering and a Singapore National Research Foundation Fellow. He earned his PhD from EPFL in 2023 and spent a year at ETH Zurich developing ultrafast devices for integrated circuits. He has pioneered new device concepts, including nanoplasma and electronic metadevices, for terahertz generation, mixing and switching. He directs i-Lab@NTU, advancing terahertz technologies for future connectivity. 

Which wall does your research or project break?  

Efficient high-performance operation of electronics in the terahertz band has been a longstanding challenge due to fundamental limitations of semiconductor devices. With frequency increases, the impact of parasitics become more severe and it ultimately dominate the active device characteristics in the terahertz band. The main limitations originate from the interfaces in semiconductor devices as well as the fundamental transport properties, which ultimately put an upper limit in what is possible in advanced analog chips for telecommunications, sensing, and beyond. I developed fundamentally new device concept to realize near-ideal metal-semiconductor interfaces to fully exploit the potentials of semiconductor materials. I have also pioneerd devices using electron nanoscale transport in gas phase instead of solid to overcome fundamental limitations of existing materials. This approaches have enabled speeds exceeding the best possible with existing device technologies.


What is the main goal of your research or project?

The generation and manipulation of terahertz (1 THz = 1 trillion Hz) waves are critical to enabling future connectivity, particularly as society increasingly depends on high-volume, low-latency data transfer. However, efficient and high-performance electronic operation in the terahertz band remains a longstanding challenge because of fundamental limitations in semiconductor devices. As operating frequencies increase, parasitic effects become increasingly severe and can ultimately dominate device performance. These limitations arise from semiconductor interfaces and intrinsic carrier-transport properties. For example, high-electron-mobility transistors (HEMTs), which are among the leading candidates for high-speed electronics, are constrained by quantum-mechanical electron injection at tunnelling junctions and by the Thomas–Fermi limit on channel transconductance. These limitations place an upper bound on the performance of advanced analog integrated circuits for telecommunications, sensing, and other emerging applications.

I have developed fundamentally new device concepts that create near-ideal meta-semiconductor interfaces, allowing the intrinsic potential of semiconductor materials to be more fully exploited. I have also pioneered devices that use nanoscale electron transport in the plasma phase, rather than in solids, to overcome fundamental material limitations.
Electronic metadevices use subwavelength-engineered displacement fields to couple patterned metallic terminals directly to a two-dimensional electron system, providing an alternative to conventional electron injection. This approach enables substantially lower contact resistance than existing semiconductor technologies. Nanoplasma switches, meanwhile, achieve picosecond electrical switching through a plasma formed within a nanoscale gap. The resulting high-density population of hot electrons exhibits an ultrashort transit time across the gap. This technology surpasses the conventional Johnson figure-of-merit, which imposes a fundamental trade-off between operating frequency and power in traditional electronic devices.

These innovative device technologies provide upstream solutions capable of delivering unprecedented combinations of speed and power, thereby establishing a foundation for future high-performance integrated circuits.

What impact does your research or project have on society?

Society is becoming increasingly dependent on technologies that need to send, receive, and process very large amounts of data. Examples include self-driving vehicles, artificial intelligence, cloud computing, smart homes, connected medical devices, advanced sensors, and the Internet of Things. As these technologies become more widely used, communication networks must become much faster, more reliable, and more energy-efficient. However, the electronic chips used in today’s communication systems are approaching their physical limits. For many years, engineers improved performance mainly by making transistors smaller. This strategy is now becoming less effective, particularly for the analog and high-frequency components that transmit and receive wireless signals. New types of electronic devices are therefore needed to support the next generation of communication technologies. My research focuses on developing fundamentally new device building blocks for wireless communication systems. These devices are designed to overcome limitations found in conventional transistors and can operate at very high frequencies, beyond 100 GHz. Such frequencies are expected to play an important role in future sixth-generation, or 6G, communication networks. The devices can also handle higher power while switching extremely quickly, enabling capabilities that are difficult to achieve using existing technologies. This research could help make future wireless networks faster, more reliable, and capable of supporting many more connected devices. It may also enable more accurate sensing, safer autonomous transportation, more responsive artificial intelligence services, and improved communication in crowded environments. Ultimately, these advances could strengthen digital infrastructure and contribute to greater productivity, safety, accessibility, and quality of life.

What advice would you give to young scientists or students interested in pursuing a career in research, or to your younger self starting in science?

I would advise young scientists, as well as my younger self, to think strategically about how their knowledge and abilities can contribute to society. We are fortunate to live in a world where clean water, nutritious food, transportation, communication, education, and healthcare are widely accessible. These achievements did not happen by chance. They are the result of generations of people who worked to understand nature, develop new technologies, and build systems that improved human life. Appreciating these achievements should encourage us to consider what contribution we can make for future generations.

A career in research is not only about publishing papers, receiving recognition, or solving technically difficult problems. It is also about identifying meaningful challenges and developing knowledge that can create long-term value. Young researchers should ask themselves why a problem matters, who could benefit from solving it, and whether their work can lead to a practical improvement in society.
Humanity continues to face major challenges, including climate change, limited natural resources, rising energy demands, unequal access to healthcare, and the need for secure and sustainable communication systems that can eventually extend beyond our planet. Creating a more sustainable and self-sufficient world will require new scientific discoveries and technologies.

At the same time, meaningful research requires patience, curiosity, resilience, and the willingness to accept failure. Many ideas will not work at first, but each failure can provide useful knowledge. My advice is therefore to remain ambitious, choose important problems, learn continuously, and never lose sight of the broader purpose of science: to expand human knowledge and improve people’s lives.



What inspired you to be in the profession you are today?

To solve real-world problems, contribute meaningfully to society, and train the next generation of scientists to address humanity’s future challenges.
 

What is one surprising fact about your research or project that people might not know?

Important discoveries are sometimes made entirely by accident.

What’s the most exciting moment you've experienced over the course of your research or project?

When experiments produce surprising results that we cannot explain.