Thin TMD transistors; diamond defect detection; roll-to-roll litho.
Researchers from Chalmers University of Technology and Stanford University fabricated transistors from three different atomically thin 2D semiconductors with channel widths as small as 25nm.
“These are some of the slimmest high-performance transistors demonstrated in two-dimensional semiconductors,” said Anton Persson, assistant professor at Chalmers University of Technology, in a press release. “What is particularly encouraging, and actually surprised us, is that the transistors remained well-behaved even when shrunk to dimensions relevant for future industrial technologies. That has been a major uncertainty in the field.”
The nanoribbon transistors were fabricated from three different monolayer transition metal dichalcogenides: molybdenum disulfide, tungsten disulfide, and tungsten diselenide. To prevent tears or peeling during fabrication, the team developed a “dog-bone” structure with an extremely narrow transistor channel and wider regions under the electrical contacts to help anchor the material in place. An advanced multi-patterning technique that etched the material in two steps from different directions was also used.
“The 2D transistors made of tungsten disulfide were especially notable, as their current density improved by more than a hundred times compared to previous demonstrations, thanks to better material quality and improved metal contacts,” said Persson.
“Our findings don’t mean that atomically thin 2D semiconductors are ready to replace silicon tomorrow,” added Eric Pop, professor at Stanford University, in a press release. “But it shows that one of the key scaling concerns may be far less limiting than previously thought.” [1]
Researchers from Rice University and DEVCOM Army Research Laboratory developed a custom Python-based software tool to rapidly analyze data from high-resolution X-ray diffraction and detect dislocation density defects in diamond and other wide-bandgap semiconductor materials. The software analyzes diffraction patterns, picks up on dislocations and irregularities in the atomic lattice, and calculates their density in a given material.
“Dislocations can disrupt how charge and heat move through the material, which impacts how efficient and reliable a device is, and how easy it is to manufacture at scale,” said Xiang Zhang, assistant research professor of materials science and nanoengineering at Rice, in a statement.
The framework was tested by analyzing four commercially available grades of single-crystal diamond with different expected levels of crystal quality. The automated workflow was able to distinguish among the materials, identifying electronic-grade diamond as having the lowest defect density and most uniform crystal quality. Heteroepitaxial diamond grown on a non-diamond substrate exhibited the highest defect density and greatest structural disorder.
The team also successfully applied the workflow to gallium nitride. Next, they plan to expand the range of materials and defect types it can analyze. [2]
Researchers from the Korea Institute of Machinery and Materials (KIMM) developed a roll-to-roll maskless digital lithography system for continuous patterning of flexible substrates with line widths below 10μm.
The system combines Digital Micromirror Device (DMD)-based exposure technology to selectively project UV light onto designated areas of a substrate. A dedicated exposure module and a high-precision web-transport control system enables continuous roll-to-roll operation, while vision-based measurements adjust the projected pattern in real time, compensating for positional errors and substrate deformation.
Because the patterns can be generated and modified through software control, the approach doesn’t need conventional photomasks and can support continuous, large-area manufacturing over long substrate lengths.
“The R2R digital lithography system is a key platform technology for the mass production of flexible electronic devices. We expect it to be used in a wide range of applications, including flexible printed circuit boards, high-resolution flexible electronics, and semiconductor packaging,” said Won Seok Chang, director of the Nano-convergence Manufacturing Research Division at KIMM, in a statement. “The technology can also be applied to digital exposure processes for patterning roll surfaces, further broadening its industrial applications.” [3]
[1] T. Peña, A.E.O. Persson, A. Krayev, et al. Scaling nanoribbon transistors with monolayer transition metal dichalcogenides. Nat. Nanotechnol. 21, 803–809 (2026). https://doi.org/10.1038/s41565-026-02161-w
[2] T. Gray, E. J. Garratt, X. Zhang, et al. “High Throughput X-Ray Characterization of Defects in Wide-Bandgap Semiconductors.” Advanced Materials 38, no. 39 (2026): e73678. https://doi.org/10.1002/adma.73678
[3] J. Choi, W. S. Lee, G. Kim, et al. DMD-based adaptive lithography system for real-time substrate deformation compensation. International Journal of Optomechatronics, 20(1). (2026). https://doi.org/10.1080/15599612.2026.2635849
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