Local probing of the field emission stability of vertically aligned multiwalled carbon nanotubes

TL;DR

This study uses a high-resolution atomic force microscope to investigate the stability of field emission from vertically aligned multi-walled carbon nanotubes, demonstrating stable emission over hours and improvements after Joule heating.

Contribution

It introduces a precise, localized probing method for assessing field emission stability of nanotubes, highlighting the effects of Joule heating conditioning.

Findings

Stable emission within 10% fluctuations over 72 hours

Current stability improves after Joule heating

High spatial resolution enables localized measurements

Abstract

Metallic cantilever in high vacuum atomic force microscope has been used as anode for field emission experiments from densely packed vertically aligned multi-walled carbon nanotubes. The high spatial resolution provided by the scanning probe technique allowed precise setting of the tip-sample distance in the submicron region. The dimension of the probe (curvature radius below 50nm) allowed to measure current contribution from sample areas smaller than 1um^2. The study of long-term stability evidenced that on these small areas the field emission current remains stable (within 10% fluctuations) several hours (at least up to 72 hours) at current intensities between 10-5A and 10-8A. Improvement of the current stability has been observed after performing long-time Joule heating conditioning to completely remove possible adsorbates on the nanotubes.