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

Area of Science:

• Materials Science
• Nanotechnology
• Electronics Engineering

Background:

• Doping is crucial for single-walled carbon nanotube (SWCNT) electronics but remains challenging due to the stable sp2 carbon network.
• Developing reliable doping strategies and control methods for SWCNTs is essential for advancing carbon-based electronics.

Purpose of the Study:

• To establish a controllable doping strategy for SWCNTs by combining palladium (Pd) encapsulation with electron-beam (e-beam) irradiation.
• To achieve precise doping modulation and enable tunable, reversible doping control in SWCNTs.

Main Methods:

• A novel approach combining Pd encapsulation with e-beam irradiation was developed for SWCNT doping.
• The acceleration voltage of the e-beam was used to modulate the p-type doping introduced by Pd encapsulation.
• SWCNT transistors were fabricated with heavily doped contacts and a lightly doped channel.

Main Results:

• The combined Pd encapsulation and e-beam irradiation strategy enabled tunable doping control from lightly to heavily doped states.
• SWCNT transistors demonstrated significantly improved performance compared to pristine devices.
• Contact resistance was reduced by half to 23 kΩ·µm⁻¹, on-current increased approximately fourfold to 24 µA·µm⁻¹, and on/off ratio exceeded 10⁷.

Conclusions:

• The developed strategy offers an effective approach to overcome challenges in efficient doping for carbon-based electronics.
• Precise doping modulation using Pd encapsulation and e-beam irradiation enhances SWCNT device performance significantly.
• This method paves the way for advanced SWCNT electronics with improved contact and channel properties.