Field emission mechanism from nanotubes through gas ionization induced nanoscale surface charging

TL;DR

This paper demonstrates that gas ionization-induced surface charging can trigger electron emission from carbon nanotubes, with potential applications in detectors and sensors.

Contribution

It introduces a novel mechanism where gas ionization causes surface charging that enables CNT field emission, supported by experimental evidence.

Findings

Gas ionization increases charge accumulation on CNTs.

ZnO nanorods enhance positive charge flux.

Surface charging triggers CNT electron emission.

Abstract

Experimental evidences reported in this letter show that the gas ionization induced positive charge accumulation can lead to the electron field emission from carbon nanotubes (CNTs) in an electrode system with proper range of gap spacing, where the CNT film with ethocel was covered with ZnO nanorods. The hypothesis for illustration is suggested that: 1) the cosmic ray ionization frequency increases 108~1010 times due to the metastable population resulted from the interaction between the gases and the CNTs; 2) the flux of positive charges is enhanced in the converged field due to the ZnO nanostructures. The resulted positive charge local density is high enough to trigger the field emission of the CNTs. The methodology may be useful in particle detectors and ionization gas sensors.