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

We produce 120-mu m-thick buckypapers from aligned carbon nanotubes. Transport characteristics evidence ohmic behavior in a wide temperature range nonlinearity 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 to 430 K a further linear contribution is necessary. The field emission properties are measured by means of a nano-controlled metallic tip acting as collector electrode to access local information about buckypaper properties from areas as small as 1 A mu m(2). Emitted current up to 10(-5) A and turn-on field of about 140 V/A mu m are recorded. Long operation, stability and robustness of emitters have been probed by field emission intensity monitoring for more than 12 h at pressure of 10(-6) mbar. Finally, no tuning of the emitted current was observed for in-plane applied currents in the buckypaper.