Mg Nanostructures Tailored by Glancing Angle Deposition

Abstract

Magnesium nanostructures, with the material characteristic of surface adatom diffusion strongly influencing the nanostructure growth during physical vapor deposition, have been fabricated by a glancing angle deposition (GLAD) technique on flat and patterned substrates at a substrate rotation speed ranging from ω = 0 rpm to ω = 10 rpm. Depending on the substrate rotation speed, the Mg nanostructures consist of different nanostructure units: a nanoblade at ω = 0 rpm (oblique angle deposition), a bundle of nanoblades at ω = 0.1 rpm, an oblate nanorod mixed with a bundle of nanoblades at ω = I rpm and an oblate nanorod at ω = 10 rpm. The formation of different nanostructure units in the samples deposited at different ω values is explained by the competition between the deposition and diffusion processes. In addition, during the oblique angle deposition of Mg, the substrate is rotated 90°, and the formed sample is composed of two layers of nanoblade arrays with an included angle γ ≈ 33° between the two layers, resulting from a lattice match at the interface. Macroscopically, the structure parameters, including the number density, width and thickness of the nanostructure units, the height of samples, and the tilting angle of the nanostructures, depend strongly on both the substrate rotation speed and the substrate features.