Ultrathin nanotubes reach 1 nanometer, opening path to smaller electronics
Researchers in Japan have created some of the world's smallest semiconducting nanotubes, structures 100,000 times thinner than a human hair. By growing molybdenum disulfide inside protective tubes of boron nitride, the researchers, ...
A few years ago, carbon nanotubes were attracting a lot of press attention. But there's a new contender in the ring, and it offers some advantages over its carbon counterpart that could tempt engineers to design products around it.
Molybdenum disulfide (MoS2) nanotubes, though still experimental in nature, point to applications in semiconductor electronics, high-resolution sensing and quantum-scale physics research.
"We achieved the synthesis of atomically precise semiconducting nanotubes with nanometer diameters. The coaxial structure, where a semiconducting MoS2 nanotube is surrounded by an insulating boron nitride (BN) nanotube, is attractive for gate-all-around transistors, one of the most advanced transistor architectures," said Associate Professor Yusuke Nakanishi from the Department of Advanced Materials Science at the University of Tokyo.
"Our paper demonstrates a way for structural control of inorganic semiconducting nanotubes at the atomic scale. And we experimentally demonstrated that the bandgap (related to how materials work as semiconductors) of the nanotubes decreases as their diameters become smaller, in agreement with theoretical predictions proposed more than a quarter century ago."
Conventional methods to produce nanotubes are usually limited to diameters above 10 nanometers, multiwalled concentric tubes, and poorly controlled or irregular atomic structures.
Nakanishi and his team synthesized 1-nanometer-wide, single-walled MoS2 nanotubes, with well-defined atomic structures. They managed this using chemical reactions inside the narrow space of BN nanotubes. The confined space constrains the MoS2 nanotubes, which would otherwise be difficult to form, and promotes well-defined atomic arrangements, essential for engineered applications.
Illustration of 1nm nanotubes. Credit: 2026 Nakanishi et al. CC-BY-ND
Previous attempts at noncarbon nanotubes either required multiple walls or internal supporting tubes which impede their potential for use as semiconductors. With a thinner tube supported from the outside, the new 1-nanometer nanotube meets all the criteria. Credit: 2026 Nakanishi et al. CC-BY-ND
The researchers formed the nanotubes inside other, larger, simpler nanotubes by heating precursor materials in a confined space. Advanced electron microscopy images and chemical mapping confirmed the presence and atomic structure of the tiny, nested tube structures. Credit: 2026 Nakanishi et al. CC-BY-ND