▎ 摘　　要

The template-directed growth process of 3D carbon nanotube-graphene junctions with nano-fillets was simulated with classical molecular dynamic (MD) simulation. The carbon nanotube, graphene and their seamlessly C-C bonded junctions were formed simultaneously on amorphous alumina templates without catalysts. The C-C bonded junctions with various fillet angles were made, and the molecular structures and tensile strength of the "as-grown" C-C junctions were determined by the MD method. Among these junctions, the 135 degrees fillet shows the most stability and improved mechanical strength, which is consistent with the experimental observations. While the fillet is a common technique that is widely used in large-scale engineering structures to reduce the stress concentration, here the nano-fillet enhances both the stability and mechanical properties of carbon nanotube-graphene junctions. This work provides a theoretical base for synthesizing high-quality carbon nanotube-graphene nanostructures via template methods.