A theoretical and experimental study on manipulating the structure and properties of carbon nanotubes using substitutional dopants

We examine the possibility of controlling nanotube growth and simultaneously manipulating the nanotube properties by adding elements in minute amounts (such as nitrogen, phosphorous, and sulfur) that are different from carbon and. the metal catalyst during the growth process. This procedure is shown to be capable of producing bamboo'type morphologies, heterodoped carbon nanotubes, and Y-junctions. This also represents a critical step toward tailoring properties and controlling nanotube architectures, thus promoting the development of novel materials with unusual electronic applications. The underlying formation mechanisms that lead to the observed structures and morphologies are elucidated using wideranging electronic structure calculations that reveal the fundamentally different nature of nitrogen, phosphorous, and sulfur during carbon, nanotube growth.