Growth Optimization and Device Integration of Narrow-Bandgap Graphene Nanoribbons

Area of Science:

• Materials Science and Engineering
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene nanoribbons (GNRs) offer tunable electronic, optical, and magnetic properties.
• Precise control over GNR width and edge structure is crucial for their application in electronic devices.
• Increasing the length of GNRs is a key challenge for device integration.

Purpose of the Study:

• To study the growth, characterization, and device integration of 5-atom wide armchair GNRs (5-AGNRs).
• To optimize on-surface synthesis conditions for achieving longer 5-AGNRs.
• To realize field-effect transistors (FETs) using narrow bandgap AGNRs.

Main Methods:

• On-surface synthesis of 5-AGNRs under ultrahigh vacuum conditions.
• Utilized bromine- and iodine-substituted molecular precursors.
• Optimized precursor coverage and precursor type to enhance GNR length.

Main Results:

• The use of iodine-substituted precursors and optimized coverage quintupled the average length of 5-AGNRs.
• Achieved significant GNR length increase, enabling device integration.
• Demonstrated the first field-effect transistor based on narrow bandgap AGNRs exhibiting room-temperature switching behavior.

Conclusions:

• Optimized growth protocols successfully bridge the gap between atomic precision and device-relevant scales for GNRs.
• The developed method allows for the fabrication of longer GNRs, crucial for electronic device applications.
• This work paves the way for advanced all-carbon electronic devices utilizing precisely engineered GNRs.