Tunable and Selective Doping Modulation in Pd‐Filled Carbon Nanotube Transistors

Doping remains one of the most difficult yet essential processes for single wall carbon‐nanotubes (SWCNTs) electronics. The highly stable sp 2 carbon network makes doping extremely difficult, rendering the development of SWCNTs‐compatible doping strategies and reliable doping‐control methods particularly challenging. Herein, we establish a controllable doping strategy by combining Pd encapsulation with electron‐beam(e‐beam) irradiation, enabling precise doping modulation. With this strategy, strong p‐type doping introduced by Pd encapsulation can be effectively modulated by acceleration voltage of e‐beam, enabling tunable, reversible doping control from lightly doped to heavily doped states. This approach allows the construction of SWCNTs transistors with heavily doped contacts and a lightly doped channel. Compared with pristine SWCNTs device, achieving a contact resistance reduced by half to 23 kΩ µm −1 , an on‐current enhanced by about four times to 24 µA µm −1 , and an on/off ratio exceeding 10 7 , providing an effective approach to overcome the challenges of efficient doping in carbon‐based electronics.