Binder-free, high-performance carbon nanotube line emitters fabricated using mechanical clamping process

•Superior contact properties were created by applying compression to a CNT forest.•CNT line emitter showed superb field emission performance and stable operation.•Excellent performances showing applicability for high-power e-beam sources.

We report a robust and scalable method to fabricate high-performance carbon nanotube (CNT) line emitters by using a macroscopic mechanical clamping process. The process utilizes a handheld, metallic tongs (which also serves as an electrode for field emission) to pick up vertically aligned, super-grown CNTs from a substrate. By applying mechanical compression to a CNT forest in the uniaxial direction, the hemicylindrical shape of CNT structure strongly held with the tongs electrode is fabricated. With robust mechanical, thermal, and electrical contact characteristics created by mechanical clamping of CNTs, the CNT line emitter shows superior field emission performance with an emission current of 43 mA, a current density of 2700 mA/cm2, and stable operation over 10 h. Furthermore, an extremely high emission current of 103 mA is achieved by clamping multiple CNT forests in a single tongs, showing prompt applicability of the present emitter for high-power electron beam sources.

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