A probe includes a substrate and a tetragonal structure disposed on the
substrate that has four end points. Three of the end points are disposed
adjacent to the substrate. A fourth of the end points extends outwardly
and substantially normal to the substrate. In a method of making a probe
tip, a plurality of tetrapods are grown and at least one of the tetrapods
is placed on a substrate at a selected location. The tetrapod is affixed
to the substrate at the selected location.