Pressure effect of low-temperature growth of multi-wall carbon nanotubes on Nickel catalyst/barrier-coated glass by thermal-CVD

In large-area field emission display applications where high stress point glass substrate is used for vacuum-sealed packaging and low cost considerations, the CNTs synthesis temperature lower than the stress point of ∼570 °C is required. In the thermal CVD processes, the catalyst passivation due to the slow carbon diffusion rate limiting and the consequent amorphous carbon formation on the catalyst surface was considered to be the main reason hampering carbon nanotube growth at low temperatures. The amount of amorphous carbon decreases apparently with the decrease of the process pressure for the low-temperature growth of CNTs. In this paper, we report a successful synthesis of vertically aligned-MWNTs on Ni/Cr coated glass (PD200) substrate at 550 and 500 °C by low pressure (8 Torr) thermal CVD with reasonably good field emission characteristics of approximate milliampere per square centimeter emission current density.