Enhanced field emission stability of vertically aligned carbon nanotubes through anchoring for X-ray imaging applications

It remains difficult to obtain a carbon nanotube (CNT) emitter that simultaneously exhibits high current density, low fluctuation, and long service time because CNTs are easily detached from the substrate in a strong electric field due to the weak adhesion between direct-growth CNTs and heterogeneous substrates. Herein, a mold-aligned transfer anchoring method is employed to anchor vertically aligned CNT film and CNT arrays on a metallic substrate using silver conductive paint via an annealing process. After 100 h of continuous testing with an initial current of similar to 2 mA and a current density of similar to 900 mA cm(-2), the decay rate of the emission current of the anchored CNT emitter decreased by similar to 88%, and the current fluctuation was similar to 57% lower than that of the unanchored CNT emitter. Furthermore, a metal wire with a width of similar to 90 mu m could be clearly distinguished by a CNT cold cathode X-ray imaging system. These results testify that the proposed anchoring method can significantly improve the stability and lifetime of CNT field emitters with a high current density, which provides a new route for developing the cold cathode of X-ray sources and other industrial applications in the vacuum electronics field.

Automated summary

A mold-aligned transfer anchoring method was used to anchor vertically aligned carbon nanotube films and arrays on a metallic substrate using silver conductive paint via an annealing process. After 100 hours of continuous testing, the anchored carbon nanotube emitter showed a decrease of around 88% in emission current decay rate and a 57% lower current fluctuation compared to the unanchored emitter. Additionally, the anchored emitter successfully distinguished a metal wire with a width of approximately 90 μm using a carbon nanotube cold cathode X-ray imaging system.