US Patent 7687981 Method for controlled density growth of carbon nanotubes

Described is a method for preparation of carbon nanotubes (CNTs) with medium to low-site density growth for use in field emission devices (FEDs). The method involves the deposition of a non-catalytic metal layer (interlayer), preferably a metallic conductor, onto the surface of a substrate, prior to the deposition of a catalytic layer (overlayer). The interlayer allows for only partial (sparse) growth of CNTs on the substrate, and helps to prevent resist layer “lift-off” when photolithographic processing is employed.