Hemispheres and spheres are formed and employed for a plurality of applications. Hemispheres are employed to form a substrate having an upper surface and a lower surface. The upper surface includes peaks of pillars which have a base attached to the lower surface. The peaks have a density defined at the upper surface by an array of hemispherical metal structures that act as a mask during an etch to remove substrate material down to the lower surface during formation of the pillars. The pillars are dense and uniform and include a microscale average diameter. The spheres are formed as independent metal spheres or nanoparticles for other applications.