Gate-tunable contact-induced Fermi-level shift in semimetal.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Low-dimensional semimetal–semiconductor (Sm-S) van der Waals (vdW) heterostructures are promising for nanoelectronics and nano-optoelectronics.
• Understanding interfacial charge transfer and Fermi-level shifts is crucial for Sm-S systems.

Purpose of the Study:

• Investigate gate-tunable contact-induced Fermi-level shift (CIFS) in semimetal single-walled carbon nanotube (SWCNT)/transition-metal dichalcogenide (TMD) heterojunctions.
• Develop a methodology to measure and analyze CIFS and its impact on device properties.

Main Methods:

• Developed a resistivity comparison methodology to measure CIFS.
• Utilized a Fermi-level catch-up model for analysis.
• Measured CIFS based on resistivity differences between contacted and uncontacted SWCNT segments.

Main Results:

• Quantified gate-tunable CIFS in SWCNT-TMD heterojunctions.
• Demonstrated that gate-tunable resistivity difference reflects relative Fermi-level positions.
• Showed CIFS modifies the Schottky–Mott rule, enabling modified Schottky barrier height determination.

Conclusions:

• The developed methodology and physical model are effective for analyzing CIFS in Sm-S systems.
• This work provides insights for designing low-dimensional reconfigurable nanodevices.
• The findings are applicable to vdW heterostructures for advanced electronic and optoelectronic applications.