Current Density-Sensitive Welding of a Semiconductor Nanowire to a Metal Electrode

In situ welding of a single ZnSe nanowire (NW) to an Au electrode has been successfully achieved by means of current-induced Joule heating. The parameter governing the welding of semiconductor NW to the metal electrode is highly dominated by the current density at the Au-ZnSe NW (M-S) contact because current density at the M-S contact can change the temperature profile along the NW. The self-heating behaviors of the Au-ZnSe NW-Au (M-S-M) nanostructure can be changed from the electrical failure of the ZnSe NW to the melting of the Au electrode localized at the M-S contact when the current density at the M-S junction was adjusted to be larger than in the NW. Consequently, the self-welding is the current density-sensitive and controllable since the current density at the M-S contact can be controlled by adjusting the contact area between the NW and metal electrode. This controlled self-welding may have potential applications in the construction of a complex nanostructure and improvement of the thermal stability of the M-S contact as well as the enhanced performance of the nanodevices based on the M-S-M nanostructure.