Enhanced gating efficiency in vertical mixed molecular transistors with deep orbital level.

Area of Science:

• Molecular electronics
• Nanotechnology
• Materials science

Background:

• Molecular junction transistors require precise orbital modulation.
• Limited transmission windows and bias stability restrict molecule selection.
• Current devices favor molecules with orbital levels near contact Fermi levels.

Purpose of the Study:

• To demonstrate effective orbital gating for molecules with deeper orbital levels.
• To enhance electrical bias stability and gating efficiency in molecular transistors.
• To develop a reliable three-terminal molecular device platform.

Main Methods:

• Utilized vertical large-area mixed self-assembled monolayers (SAMs) configuration.
• Employed ion gel gating in an Au-molecule-graphene junction.
• Investigated prototypical alkanethiol-based molecules with deeper orbital levels.

Main Results:

• Achieved effective orbital gating with enhanced bias stability and gating efficiency.
• Demonstrated notable channel conductance modulation via a transition from direct to Fowler-Nordheim tunneling.
• Observed superior gating efficiency in mixed SAM molecular transistors due to suppressed field screening.

Conclusions:

• Mixed SAMs enable orbital gating for molecules with deep orbital levels.
• The developed device platform offers enhanced electrical bias stability and gating efficiency.
• This work paves the way for reliable three-terminal molecular devices using a wider range of molecules.