Fabrication of Carbon Nanotube Field-Emission Cathodes by Laser-Induced Transfer of Carbon Nanotubes and Silver Paste

A new laser material-transfer scheme for transfer printing both the silver-paste and the carbon-nanotube (CNT) thin film in pattern simultaneously is reported. The transfer mechanism is discussed and demonstrated to be unlike to those conventional laser-transfer approaches which only the material on the laser-irradiated region is transferable, the present scheme is capable of transferring the materials on the unexposed locations as well. The transferred CNTs are directly on the top of the silver paste which is a suitable configuration for application to the CNT field-emission cathodes. Measurements demonstrate that the fabricated CNT field-emission cathodes exhibit a low turn-on field of 2.5 V/μm at current density of 10 μA/cm². A lifetime test also demonstrates that the device is stable. By a single laser shot, this study successfully demonstrates that the transferred CNTs are preserved on the silver paste´s surface that requires no subsequent post-treatment processes. Moreover, all the fabrication steps are executable at room temperature and in the ambient environment.