Field emission-from arrays of free-standing carbon nanotubes grown by ICP-CVD

Carbon nanotubes (CNTs) have been considered as a prime candidate material of cold cathode emitter for field emission (FE) application. No matter whether the cathode assembly is fabricated by screen printing or in-situ chemical vapor deposition (CVD), the strict requirement of high emission uniformity on a large area display panel still remains a great challenge. There have been a large amount of publications demonstrating the ability of growing large area patterned well-aligned multi-walled carbon nanotubes with uniform diameter and height by thermal CVD. The field emission performance however was hampered due to high carbon nanotube density (> 10⁸ cm^-2) and low emission density (∼10⁴ cm^-2), which is not attributed solely to the electrical field screening effect. In this report, we used electron beam lithography (EBL) followed by metal deposition/lift-off to define the position and size of nickel catalyst and grew CNTs using inductively-coupled plasma (ICP) CVD. The EBL has been proven to be a straight forward method to define an array of catalyst metal dots with designated size and inter-distance. The ICP-CVD has been shown to grow free-standing vertically-aligned CNTs with uniform diameter and height. And then a gripper-type nano-object manipulation assembly inside a scanning electron microscope (SEM) was utilized to measure the field emission from individual carbon nanotube.