In this study, we have developed a novel technique for growing carbon nanotubes (CNTs) directly on Ni-caps. The gas phase nucleated CNTs were first deposited on the Ni-caps, followed by the growth of CNTs through a microwave induced heating process. In this process a specially designed substrate holder, W-coil on SiC cylinder, is used for resulting in rapid heating-up of the substrate via the absorption of the microwave power and forming appropriated temperature profile for the dissociation of ferrocene/CH4 prior to the formation of CNTs in gas phase in adjacent to Ni-caps. The as-nucleated CNTs are very small in size, about 10 nm in diameter and hundreds nanometer in length. The CNTs grew rapidly on the nuclei, to around 80 nm in diameter and several tens of micron in length, within 10 min. The CNTs exhibit large electron field emission capacity ((Je)g=5.8 mA/cm2 at 12.5 V/μm applied field) with (E0)g=8.0 V/μm turn-on field. The electron field emission properties of CNTs-coated Ni-caps are very stable after burn-in for a few voltage cycles. Thus formed Ni-caps can potentially be used as electron sources for cathode ray tubes (CRT).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Materials Chemistry
- Electrical and Electronic Engineering