Growth of vertically aligned carbon nanotube bundles by a cost-effective non-lithographic technique for high-performance field emission electron source

In the present study, a non-lithographic method is utilized to create patterns of vertically aligned carbon nanotubes (VACNTs). A 20-nm-thick Au layer and a 50-nm-thick Al layer were deposited onto the silicon substrate by thermal evaporation using a steel mesh to create patterns, followed by CNT growth at 900 °C using thermal chemical vapour deposition (TCVD). The effect on the growth of VACNTs on various patterned substrates is studied using a field emission scanning electron microscope (FESEM) and Raman spectroscopy. The field emission characteristics of VACNT bundle patterns produced on patterned surfaces were examined. At 3 V/μm, the current density of CNT film grown on non-patterned substrate is 3.2 mA/cm², which rises to 16.1 mA/cm² for the circular pillar of VACNT bundles. Greater spacing between VACNT bundles in the circular pattern reduces electric field screening, resulting in a 500 % increase in current density compared to other samples.