In order to improve electron transport, in situ Joule heating of an Au-ZnSe nanowire-Au (M-S-M) nanostructure is conducted inside transmission electron microscopy (TEM) until the Au metal is molten at the reversely biased Au-ZnSe nanowire (M-S) nanocontact. The observed microstructural evolution is responsible for the electron transport property changes, i.e. a nonlinear to linear transformation in the current-voltage (I - V) relationship was measured in situ before and after the Joule annealing. The linear characteristic in the I - V relations...