Growth and integration of aligned carbon nanotube-based field emission cathode for electron gun device-level fabrication

This study elucidates on growth and integration of aligned carbon nanotube-based field emission cathode for electron gun-device fabrication. Particularly, it emphasises on field emission (FE) and thermal transport (TT) properties of carbon nanotube (CNT) arrays with controlled atomistic defects (AD) to design a cold cathode (CC) for electron gun. To assess the influence of AD on FE and TT, aligned undoped (pure CNT) and N-doped herringbone (doped CNT) were fabricated using droplet-assisted solvent-thermolysis to use them as CC. Results demonstrated that doped CNT with higher degree of AD exhibited a lower turn-on field in FE in comparison to pure CNT could be ascribed to N addition in carbon lattice. Ambiguously, doping-mediated AD in doped CNT helps to achieve the best FE but lowers TT with significant decrease in thermal conductivity (111 to 5.1 W/m.k at room temperature) in comparison to pure CNT. Based on the FE behavior, a doped CNT arrays-based cathode was integrated into an electron gun, which exhibited maximum emission current of 81.3 mA/cm² at a grid voltage of 2 kV.