Growth of crystalline Ag nanorods by ion beam sputter glancing angle deposition

Glancing angle deposition (GLAD) is an efficient physical vapour deposition process to sculpt columnar nanostructures. When the particle flux reaches the substrate under a highly oblique angle β (β∼80 , as measured to the substrate normal), inherent self-shadowing mechanism causes growth of needle-like structures. Here, ion beam sputter glancing angle deposition of Ag nanostructures with different morphologies on planar and pre-patterned substrates either at room temperature (RT) or elevated substrate temperatures are demonstrated. Randomly distributed nanostructures are observed on planar substrates, while patterned templates with different periodicity yield growth of well organised periodic structures at RT. A broad angular divergence of the sputtered particle flux is minimised by a slit aperture. At room temperature, columnar structures are observed, irrespective of the presence of the slit aperture. At elevated temperatures (300 C, 350 C) and collimated particle flux in the presence of the slit aperture, however, accelerated surface diffusion causes the growth of crystalline nanorod- and nanowire-like structures. In the absence of the slit aperture, the particle beam divergence is higher, leading to island- and mountain-like crystalline structures that are found at elevated temperatures.