In a recent collaborative effort, the research groups led by Zhao Weisheng and Lin Xiaoyang from Beihang University, along with Peng Lianmao and Xu Haitao from Peking University, have made a significant breakthrough in the realm of carbon nanotube field-effect transistors (CNTFETs). Their research, which has been published in Nature Communications, reveals that gamma-ray irradiation can markedly enhance the performance of CNTFET devices.

As silicon-based transistors near their physical limitations, CNTFETs have risen to prominence as a leading candidate technology for the post-Moore era. This is attributed to their immunity to short-channel effects and their ability to operate at high speeds with low power consumption. Nevertheless, the quality of the interface between carbon nanotube materials and the dielectric layer has remained a crucial factor hindering performance enhancements. Residual organic molecules at this interface elevate the density of interface states, leading to a deterioration in subthreshold swing and an increase in off-state current.

To tackle this issue, the research team proposed the use of high-energy gamma-ray irradiation to selectively decompose and reconfigure residual organic molecules on the carbon nanotube surface. This approach significantly improved the interface quality. The study found that gamma-ray irradiation caused minimal harm to the carbon nanotubes themselves, while promoting the transformation of low-bond-energy chemical bonds in organic molecules into high-bond-energy bonds. This reduction in interface shallow-level defect states effectively curbed off-state leakage current and subthreshold swing degradation.

Employing this method, the team successfully reduced the off-state current density of the device under operating voltage to 112.2 pA/μm, nearing the low-power target of 100 pA/μm. The on-off ratio reached approximately 10⁵, placing it among the top levels for network-like CNTFETs.

Furthermore, the research team designed a CNTFET with a quasi-surrounding-gate structure. This design enhances gate control efficiency and device radiation resistance through dual-gate regulation from both the top and bottom. Experiments demonstrated that even under a total irradiation dose as high as 100 Mrad(Si), the threshold voltage variation of the device remained within 10%. This showcases a radiation resistance that far surpasses that of traditional silicon-based devices.

This study offers an efficient and scalable industrial pathway for the post-treatment of CNTFETs and establishes a technical foundation for their deployment in high-radiation environments, such as deep-space exploration and nuclear energy applications.