Phonon-assisted electron emission from individual carbon nanotubes

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The phenomenon of electron emission from one-atom-thick surfaces remains poorly understood.
• Lateral electron emission, specifically from the sides of nanostructures, has not been extensively investigated.

Purpose of the Study:

• To thoroughly investigate lateral electron emission from one-atom-thick surfaces for the first time.
• To discover and characterize a new electron emission mechanism in electrically biased carbon nanotubes (CNTs).

Main Methods:

• Experimental measurements of lateral electron emission from individual carbon nanotubes (CNTs).
• Theoretical modeling using coupled Boltzmann equations for electrons and optical phonons.
• Analysis of electron overflow from the one-atom-thick CNT surface.

Main Results:

• Discovery of a novel electron emission mechanism termed 'phonon-assisted electron emission'.
• Experimental data is well-described by a kinetic model involving hot forward-scattering optical phonons.
• Electrons absorb optical phonons, enabling them to escape the one-atom-thick CNT surface.

Conclusions:

• Phonon-assisted electron emission is a newly identified mechanism for lateral electron escape from one-atom-thick surfaces.
• This mechanism is facilitated by the absorption of hot optical phonons by electrons in biased CNTs.
• The characteristics of this emission (low voltage, high density, side emission) make it highly promising for electron source applications.