A generic process of growing aligned carbon nanotube arrays on metals and metal alloys

摘要

Aligned carbon nanotube ( CNT) arrays are integral towards the development of several applications such as field emission, interconnects in silicon technology, and chemical and biological sensing. Even though the synthesis of CNTs has been described extensively in the literature, there has not been significant success in growing uniform, well-aligned CNT arrays on pure metal surfaces other than metals that catalyse CNT growth themselves. In this paper, we describe a method of growing aligned CNT arrays on a variety of pure metals, metal alloys, and conductive ceramics using a bimetallic iron/alumina composite catalyst at low temperatures ( 550 to 700 degrees C). We believe that the addition of alumina to the iron catalyst significantly reduces catalyst-metal underlayer interactions that have traditionally proven to be a barrier for the growth of CNTs on metals. The alumina also minimizes surface diffusion of iron and allows the formation of a high density of uniformly dispersed catalyst nanoparticles to act as nucleation sites for well-aligned CNT arrays. Despite the presence of non-conducting alumina from the catalyst, the contact resistance between the CNTs and the metal underlayer was observed to be quite low, emphasizing the usefulness of this approach to practical applications. Our process was successful in growing aligned CNTs even on commercial steel plates and may be applicable for substrates of any shape or size.