Direct growth of carbon nanotubes on a micro-sized cobalt tip and characterization of electron-emission properties

Carbon nanotubes (CNTs) are synthesized directly on an electrically conducting cobalt (Co) tip of 1 μm in diameter, without any additional buffer or catalyst layer, through inductively coupled plasma-chemical vapor deposition (ICP-CVD). The nanostructures, morphologies, and crystalline structures of all the CNTs are analyzed through field emission SEM, high-resolution TEM, and Raman spectroscopy. Compared with the conventional emitter, which has a configuration of CNTs/Co(catalyst)/TiN(buffer)/W-tip, the CNTs/Co-tip field emitter proposed in this work show a noticeably improved performance in the electron-emission characteristics as well as in the stability of the emission current due to prolonged operation (up to 50 h).