Electrical failure behaviors of semiconductor oxide nanowires.

Electrical failure studies on semiconductor oxide nanowires (NWs) were performed in?situ inside a transmission electron microscope (TEM). A high driven current leads to a sudden fracture of the SnO2 NW and creates ultra-sharp and high aspect ratio tips at the broken ends, which provides a simple and reliable way for in?situ nanoprobe fabrication. As a comparison, the TiO2 NW fails due to Joule-heating-induced melting and retracts back into a nanosphere. The distinct behaviors are rooted in the different bonding nature. The strong ionic bonding between titanium and oxygen ions preserves the stoichiometry, while the covalently bonded SnO2 NW decomposes before melting. The decomposition process is observed by resistively heating an SnO2/TiO2 core?shell structure. It has been demonstrated that the needle-like geometry greatly enhanced field emission properties of SnO2 NWs.