Figure 3

I - V curves recorded for WO ₃ nanowire with asymmetric contacts. (a) I-V curves recorded for an individual WO₃ nanowire (with a diameter of 100 nm) with asymmetric contacts between the two ends of the nanowire and electrodes under different temperatures in vacuum. Inset in the upper left corner is a SEM image of the WO₃ nanowire with asymmetric contacts. Inset in the lower right corner shows the I-V curve recorded within a small sweep range near zero bias. (b) I-V curves recorded for the WO₃ nanowire with different bias sweep rates at 425 K. Inset shows the close view of the I-V curves near zero-bias.