Synthesis of Sn nanowire by template electrodeposition and its conversion into Sn nanosolder

Abstract

Electrodeposition of Sn within porous anodic aluminum oxide (AAO) template was used to synthesize Sn nanowires. Ag seed layer was sputtered upon AAO template firstly, then the Sn nanowires were electroplated upon the seed layer. After electrodeposition the Ag seed layer was removed and the AAO template was dissolved in order to obtain Sn nanowires finally. The diameter of Sn nanowires was about 200 nm, being consistent with the template pore size, while the length of nanowires had a linear growth rate of approximately 2.49 μm/min. X-ray diffraction (XRD) and electron diffraction revealed that individual Sn nanowire was single crystal without preferential growth direction. The surface of the nanowire was wrapped by a thin SnO film (~5 nm thick), as verified by transmission electron microscopy (TEM) observation and X-ray photoelectron spectrometer (XPS) analyses. The synthesized Sn nanowire powders had a dark brown color, which comes from the surface SnO layer. Through the differential scanning calorimetry (DSC) analysis, the melting point of Sn nanowires was determined as 231.73 °C, which is about 2.7% lower than the pure Sn particles. Fabrication of Sn nanosolders from Sn nanowires was tried using liquid bath melting method. It was found that Sn nanowires could convert into spheroidal nanosolder in liquid paraffin, which demonstrated a novel technology to fabricate nanosolders used for nanoscale interconnections.