In situ observation and thermal alloying induced shape manipulation of FIB-grown Pt composite nanowires

Abstract With the assistance of in situ heating techniques in the transmission electron microscope, the morphology change of the Pt nanowires which were deposited by focus ion beam has been monitored under different temperatures. With a drastic shape expansion, a significant bending has been observed abruptly above 250 °C. The energy dispersive X-ray spectroscopy mapping indicated the asymmetrical distribution of carbon (C), platinum (Pt) and gallium (Ga) within the Pt nanowires while the diffraction analysis revealed the crystalline formation of Ga-Pt alloys during the heating process. The in-situ exploration discovered that besides the recrystallization of Pt nanoparticles, the asymmetrical volume expansion from the Ga-Pt alloys formation should be another factor which induces the shape variation of the heated Pt nanowires.