Growth mechanism of Y-junctions and related carbon nanotube junctions synthesized by Au-catalyzed chemical vapor deposition

Y-junctions and related carbon nanotube (CNT) junctions were synthesized by Au-catalyzed chemical vapor deposition. The catalyst was prepared by evaporating a 10-nm-thick Al2O3 film and a 1-nm-thick Au film on a Si substrate. Based on thorough investigations under a high-resolution transmission electron microscope, the CNT junctions were proved to be formed by a unified catalyst-merging mechanism. Different merging processes resulted in different morphologies, such as Y-shaped, T-shaped, multi-leveled, multi-terminal and L-shaped CNT junctions.