Multi-tasking transistor; p-bit fabrication; tiny MoS2 nanotubes.
Researchers at Pohang University of Science & Technology (POSTECH) developed a zinc oxide (ZnO) and tellurium (Te) heterojunction transistor technology that exhibits negative differential transconductance (NDT), where current decreases over a certain voltage range.
By precisely controlling overlap length between the two materials, the team realized double negative differential transconductance (D-NDT), where the phenomenon occurs twice in succession within a single device. This enables the device to perform multiple circuit functions simultaneously, potentially simplifying circuit design and increasing data processing speed.
The researchers implemented a frequency quadrupler that converts one input signal into four output signals, a task that would normally require multiple transistors. In circuit experiments, the researchers found that data processing speed increased fourfold within a single input signal cycle.
“This study demonstrates the possibility of implementing complex circuit functions at the level of a single device,” said Byoung Hun Lee, a professor at POSTECH, in a press release. “We expect this technology to be widely applicable to the development of ultra-compact AI devices and three-dimensional integrated, highly-density semiconductor systems.” [1]
Researchers from Tohoku University and the National Institute of Standards and Technology (NIST) fabricated an integrated spintronic probabilistic bit (p-bit) on a silicon chip.
A key building block for probabilistic computers, the p-bit fluctuates stochastically between 0 and 1 by utilizing intrinsic physical randomness. Transistors and lower interconnect layers were fabricated on SkyWater’s 130nm CMOS process, while superparamagnetic nanodevices and upper electrodes were then integrated using Tohoku’s spintronic device fabrication facilities.
In tests, the device demonstrated stochastic fluctuations of the output voltage over time and controllability of the time-averaged output through an input voltage, two essential characteristics for p-bit operation. The researchers believe the approach is a step toward large-scale practical implementation of probabilistic computers. [2]
Researchers from the University of Tokyo, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo Metropolitan University, University of Tsukuba, and University of Osaka created 1nm wide single-walled semiconducting nanotubes made by growing molybdenum disulfide inside protective tubes of boron nitride.
“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 Yusuke Nakanishi, an associate professor from the Department of Advanced Materials Science at the University of Tokyo, in a statement. “Our paper demonstrates a way for structural control of inorganic semiconducting nanotubes at the atomic scale. And we experimentally demonstrated that the bandgap of the nanotubes decreases as their diameters become smaller. […] Our nanotubes could offer a more reliable way to build ultrasmall semiconductor channels with consistent properties.”
Next, the researchers aim to increase the nanotube length from the current limit of several hundred nanometers to around 1 micrometer. [3]
[1] J. H. Jun, B. G. Kim, M. S. Kang, et al. “Multi-Functional ZnO–Te Heterojunction Devices Enabling Compact Frequency Quadrupler.” Advanced Functional Materials 36, no. 42 (2026): e74948. https://doi.org/10.1002/adfm.74948
[2] J.-Y. Yoon, N. Caçoilo, A. Madhavan, et al. 130-nm CMOS-integrated superparamagnetic tunnel junction-based p-bit, IEEE Electron Device Letters (2026). https://dx.doi.org/10.1109/led.2026.3696800
[3] Y. Nakanishi, R. Senga, A. Furusawa, et al. “Confined growth of armchair MoS2 nanotubes at the 1-nm limit,” Science: June 4, 2026 https://doi.org/10.1126/science.aee3446
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