Typical I-V curves recorded with different bias sweep ranges. The black, red, and green curves are recorded for an individual WO3 nanowire at room temperature in vacuum with 1, 3, and 5 V, respectively. Inset in the upper left corner is a SEM image of the WO3 nanowire device. Inset in the lower right corner shows the I-V curves recorded within a small sweep range after large positive and negative bias excursion. Inset in the upper right and lower left corner are schematic diagrams showing the movement of positively charged oxygen vacancies.
He et al. Nanoscale Research Letters 2013 8:50 doi:10.1186/1556-276X-8-50