Structural evolution and graphitization of metallorganic-Pt suspended nanowires under high-current-density electrical test

We present a real-time investigation of the dramatic structural evolution occurring in metallorganic-Pt suspended nanowires (SNWs) (20 nm size) under high-current-density electrical test. SNWs are fabricated by electron beam-induced deposition and consist of Pt nanograins (2-3 nm) embedded in a carbonaceous matrix. As current increases, the Pt-C granular material transforms into Pt-depleted, graphitized C with a two-stage process. First, Pt coalescence into big grains (10-15 nm) is observed, then, for current density approaching 10(7) A/cm(2), grains are depleted by Pt electro- and thermomigration, leaving a graphitized C matrix. The graphitic-C wire eventually breaks forming a nanosize gap.