Engineering a Well-Aligned Composition-Graded CuSi Nanorod Array by an Oblique Angle Codeposition Technique

A well-aligned composition-graded CuSi nanorod array structure has been fabricated by a simple oblique angle codeposition technique in a physical vapor deposition system. The Cu and Si graded composition distribution in the nanorods was confirmed by their elemental mapping and depth profiles. The crystal structure evolution with the nanorod length was revealed by both electron and X-ray diffractions. The size evolution of the CuSi nanorods followed a power law, which results from the combination effects of geometric shadowing and limited surface atomic diffusion. Such a graded composition distribution could relax the stress between the nanorods and the substrate, and is promising for applications where improved nanorod−substrate adhesion is required.