Horizontal Arrays of One-Dimensional van der Waals Heterostructures as Transistor Channels.

Area of Science:

• Nanoelectronics
• Materials Science
• Solid State Physics

Background:

• The interface between carbon nanotubes and dielectrics is critical for high-performance transistors.
• Hexagonal boron nitride (h-BN) can improve interfaces by reducing interface state density.
• Fabricating coaxial heterostructures of carbon nanotubes and h-BN has been challenging due to isolation requirements.

Purpose of the Study:

• To develop a strategy for fabricating isolated van der Waals heterostructure arrays of carbon nanotubes and boron nitride nanotubes.
• To create hysteresis-free transistors utilizing these heterostructures as interfacial layers.
• To understand the strain and inhomogeneity within individual heterostructures.

Main Methods:

• Aligned carbon nanotubes on quartz were used as templates.
• A dry transfer technique created air-suspended carbon nanotube arrays.
• Boron nitride nanotubes were coaxially wrapped around the suspended carbon nanotubes.
• Transistors were fabricated with boron nitride as an interfacial layer.
• Characterization of individual heterostructures was performed over trenches and on a substrate.

Main Results:

• Successfully fabricated isolated arrays of carbon nanotube/boron nitride heterostructures.
• Fabricated transistors exhibited hysteresis-free characteristics due to improved interfaces.
• Gained insights into strain on inner carbon nanotubes and inhomogeneity of boron nitride coating.
• Device fabrication and characterization did not require elaborate electron microscopy.

Conclusions:

• The developed strategy enables practical fabrication of one-dimensional van der Waals heterostructures.
• This method facilitates the use of improved nanotube-dielectric interfaces for advanced nanoelectronic devices.
• The findings pave the way for energy-efficient computation using novel heterostructure materials.