Transport and field emission properties of buckypapers obtained from aligned carbon nanotubes

TL;DR

This study investigates the electrical transport and field emission characteristics of 120-micrometer thick buckypapers made from aligned carbon nanotubes, revealing ohmic behavior, tunneling conduction, and stable electron emission properties.

Contribution

It provides detailed analysis of transport mechanisms and field emission stability in buckypapers, introducing local emission measurements with a nanocontrolled tip.

Findings

Transport is mainly due to thermal fluctuation induced tunneling.

Buckypapers exhibit stable field emission with a turn-on field of about 140 V/μm.

Emitters remain stable over 12 hours of operation.

Abstract

We produce 120 um thick buckypapers from aligned carbon nanotubes. Transport characteristics evidence ohmic behavior in a wide temperature range, non linearity appearing in the current-voltage curves only close to 4.2 K. The temperature dependence of the conductance shows that transport is mostly due to thermal fluctuation induced tunneling, although to explain the whole temperature range from 4.2 K to 430 K a further linear contribution is necessary. The field emission properties are measured by means of a nanocontrolled metallic tip acting as collector electrode to access local information about buckypaper properties from areas as small as 1 um2. Emitted current up to 10-5A and turn-on field of about 140V/um are recorded. Long operation, stability and robustness of emitters have been probed by field emission intensity monitoring for more than 12 hours at pressure of 10-6 mbar. Finally, no tuning of the emitted current was observed for in plane applied currents in the buckypaper.