Transmission-electron-microscopy observation of Pt pillar fabricated by electron-beam-induced deposition

Pt pillars with a waist size of 20 nm and a length of 300 nm were fabricated by electron-beam-induced deposition and characterized by transmission electron microscopy before and after annealing or radical oxygen gas exposure. The average grain size of Pt nanocrystals was found to increase from 1.9 +/- 0.3 to 4.3 +/- 1.0 nm after annealing at 450 degrees C. The Pt nanocrystals seem to coalesce with annealing. This result indicates that the change in the electron transport of Pt nanowires after annealing is due to the physical coalescence and the increase in the grain size of the Pt nanocrystals. The Pt nanocrystals were found to appear at the tip surface owing to the removal of the amorphous carbon matrix by radical oxygen gas exposure.