Geometric effects on the mechanical strengths of strong nanocrystalline rhodium sub-micron structures

Abstract

Sub-micron scale nanocrystalline rhodium pillars were fabricated by electron beam lithography and electroplating techniques. The fabricated specimens included solid core pillars and columnar structure with more complex cross-sectional geometries, including x-shaped and annulus shaped. Among these specimens, two groups of sub-micron scale annulus structures with sidewall thicknesses of 250 and 205 nm were fabricated. All of the structures have outer diameters of ~1 μm and consist of average grain size smaller than 22 nm. Uniaxial compression results reveal these rhodium pillars are very strong with true flow stresses exceeding 5 GPa and are not sensitive to the sample cross-sectional geometries.