Direct Growth of Bent Carbon Nanotubes on Surface Engineered Sapphire

Bending of horizontally aligned single-walled carbon nanotubes (SWNTs) was achieved on surface engineered single-crystal sapphire (α-Al2O3). The SWNTs grown on the r-plane sapphire are aligned along the specific crystallographic [11̅01̅] direction due to the lattice-oriented growth, and we created artificial step structures perpendicular to this SWNT growth direction. These steps changed the nanotube growth direction from the [11̅01̅] to the step direction with the bending angle of nearly 90°. Effects of the bending structure on electron transport property were studied. Our approach to combine the lattice-oriented growth with the step-templated growth will offer a new route toward the growth of two-dimensionally controlled SWNT architectures for future nanoelectronics.