Growth of uniformly aligned nanorod arrays by oblique angle deposition with two-phasesubstrate rotation

Abstract

Due to the shadowing effect, the oblique angle deposition technique can produce nanorodstilted toward the incident deposition flux. Periodic posts serving as seeds on a substrateallow the fabrication of nanorod arrays with controllable separations. However, in aconventional oblique angle deposition with no substrate rotation, nanorods grow fasteralong their widths in the direction perpendicular to the plane of incident flux. Thisanisotropic growth can result in ‘fan-out’ shapes of nanorods that touch eachother due to the faster growing widths. Asymmetric two-phase substrate rotationwas designed to eliminate the side growth in oblique angle deposition. In thismethod, the growing rods are exposed to the deposition flux from all angles withsome portion of a rod surface receiving more flux than the rest. We fabricatedwell-aligned Si nanorod arrays with uniform sizes from templates arranged insquare and triangular lattices using this two-phase substrate rotation method.