The relentless quest to make microprocessors smaller, faster, and more efficient has led researchers to the edge of a revolutionary breakthrough. For decades, silicon has been the cornerstone of microprocessor technology, but as the demand for ever-shrinking, more powerful devices grows, silicon has started to hit its physical limitations. Enter molybdenum disulfide (MoS₂), a promising alternative to silicon that has caught the attention of engineers and scientists worldwide. A team of engineers at Fudan University has made a remarkable leap forward by designing, building, and successfully running a 32-bit RISC-V microprocessor that uses MoS₂, rather than traditional silicon, as its semiconductor material. Their groundbreaking work, published in the prestigious journal Nature, signals a potential paradigm shift in the field of semiconductor design.
Silicon’s Struggles and the Need for a Change
For decades, silicon-based technology has been the foundation of the modern electronics industry. Silicon is affordable, reliable, and has proven itself effective in a variety of applications, from computers to smartphones. However, as engineers push the limits of Moore’s Law—the prediction that the number of transistors on a microchip doubles approximately every two years—the physical limitations of silicon have become apparent. Silicon transistors can only be made so small before quantum effects start to interfere with their operation, and the material’s ability to conduct electricity at smaller scales is no longer sufficient to meet the demands of modern electronics.
This plateau has forced scientists to look for alternatives. Graphene, a two-dimensional (2D) material known for its extraordinary conductivity and strength, emerged as a promising candidate. But while graphene is an excellent conductor, it lacks the semiconducting properties necessary for use in transistors, making it unsuitable for microprocessors.
Thus, the search continued for materials that could combine the benefits of 2D structures with semiconducting properties, and researchers turned their attention to MoS₂—a material that may hold the key to overcoming the limitations of silicon.
The Rise of Molybdenum Disulfide: A Revolutionary Material
Molybdenum disulfide (MoS₂) is a two-dimensional material composed of a single layer of molybdenum atoms sandwiched between two layers of sulfur atoms. Unlike graphene, MoS₂ is a semiconductor, making it an ideal candidate for use in microprocessors. While its atomic structure is similar to that of graphene, MoS₂’s unique properties, including a sizable bandgap, allow it to function as a semiconductor—a crucial characteristic for the construction of transistors.
However, MoS₂ is not a perfect 2D material. Its atomic layers are bonded at a slight angle, creating a slightly zigzag surface that differentiates it from truly flat materials like graphene. Despite this, its two-dimensionality and semiconducting nature make it an exciting alternative to silicon in microprocessor design, and the Fudan University team saw an opportunity to build a functional processor using this material.
A New Approach to Processor Design
The Fudan University team’s challenge was to use MoS₂ to create a fully functional microprocessor, which involved overcoming several technical hurdles. Traditional semiconductor fabrication methods, such as doping (introducing impurities to alter conductivity), were not directly applicable to MoS₂ due to its unique atomic structure. Instead, the team had to adopt an entirely new approach to wiring the transistors together.
The first step in the design was to place MoS₂ sheets onto a sapphire substrate—a common method used to support ultra-thin materials. This created a foundation upon which the microprocessor would be built. Due to the thin nature of the MoS₂ sheets, the researchers had to use intricate wiring techniques to connect the transistors, as simple doping wouldn’t suffice. The wires themselves were used to adjust voltage thresholds, allowing the transistors to function as needed for computing operations.
Once the transistors were wired together, the team added logic gates—critical components for performing calculations and processing information. Depletion-mode inverters were used to build these gates, further demonstrating the team’s ability to tailor MoS₂’s properties for complex computing tasks.
Optimizing the Processor’s Performance
With the basic transistor and logic gate architecture in place, the next step was to optimize the microprocessor’s speed and functionality. The researchers used the longest path distance between transistors to determine the chip’s maximum processing delay, which ultimately set the clock speed for the processor. Although the clock speed of this prototype chip is in the kilohertz range—a far cry from the gigahertz speeds seen in modern processors—the achievement is significant, considering this is the first time a microprocessor has been successfully built using MoS₂.
One of the most impressive aspects of the project was the high yield of the chips. The overall yield, meaning the number of functional processors relative to the number of chips produced, was measured at approximately 99.9%. The chip-level yield was even higher, at 99.8%, which is an excellent result, considering the complexities involved in working with new materials like MoS₂.
Building a Functional 32-Bit RISC-V Processor
The final test processor built by the Fudan University team consisted of 5,900 transistors and was capable of running a 32-bit version of the RISC-V instruction set, a popular open-source architecture. To test the processor, the team successfully ran a simple program that added two 32-bit numbers, demonstrating that the chip could perform basic arithmetic tasks, a fundamental operation for any processor.
This achievement not only demonstrated the feasibility of MoS₂ as a semiconductor material for microprocessors but also proved that a fully functional 32-bit processor could be built using this material. The team suggests that this chip could be the most sophisticated non-silicon microprocessor ever created, marking a significant milestone in semiconductor research.
Challenges and the Path Forward
While the achievement is impressive, the researchers acknowledge that the MoS₂-based processor is not yet ready for real-world applications. The chip operates at relatively low speeds, and the technology requires further refinement before it can be used in high-performance computing devices. Nevertheless, the team suggests that with some adjustments and optimizations, MoS₂ chips could be useful for niche applications, particularly in environments where extremely low voltage is required.
For example, MoS₂-based processors could find applications in low-power devices, where traditional silicon chips may be overkill, or in remote or energy-efficient systems that require processors to run on minimal power. While the technology is still in its infancy, the potential is enormous, and this breakthrough could eventually lead to a new era in microprocessor design.
The Broader Implications of MoS₂ in Semiconductor Technology
The success of the Fudan University team’s MoS₂-based microprocessor opens the door to a host of exciting possibilities in the world of semiconductors. As silicon begins to reach its physical limits, alternative materials like MoS₂ could provide a new avenue for advancing processor technology. Not only could MoS₂ allow for the creation of smaller, more efficient microprocessors, but its unique properties might also enable new types of computing altogether.
In addition to microprocessors, MoS₂ and other 2D materials are being explored for use in a range of electronic devices, including transistors, memory storage, and sensors. As research in this area continues to advance, it’s likely that MoS₂ will play an increasingly important role in the next generation of electronic devices.
Conclusion: A Step Toward the Future of Microprocessors
The development of a 32-bit RISC-V microprocessor using MoS₂ by the engineers at Fudan University is a groundbreaking achievement in the world of semiconductor technology. While it may not yet be ready for mass production or real-world applications, the success of this project demonstrates the immense potential of 2D materials like MoS₂ in transforming the future of computing. As researchers continue to push the boundaries of what is possible with alternative materials, the dawn of a new era in microprocessor technology may be closer than ever. With continued innovation and refinement, MoS₂ could one day replace silicon as the material of choice for the next generation of microprocessors, heralding a new age of ultra-efficient, ultra-small, and high-performance computing devices.
Reference: Peng Zhou, A RISC-V 32-bit microprocessor based on two-dimensional semiconductors, Nature (2025). DOI: 10.1038/s41586-025-08759-9. www.nature.com/articles/s41586-025-08759-9