Figure 2
Characterization of ambipolar behavior.
(a) Transfer characteristics of a back-gates device fabricated with a 6 nm thick WSe2 flake exfoliated on 20 nm SiO2 substrate before and after annealing. The hole current is improved by 1 order of magnitude and the electron current remains unvaried. In this case, the positive and negative Vg sweeps were taken separately, thus the non-continuity of the curves at Vg = 0 V. Both curves were taken with VDS = 1 V. (b) Transfer characteristic of the double-gate device presented in Fig. 1 measured with floating program gates. The device shows a good ambipolar behaviour, with ON currents of 4 μA for electrons and of 0.25 μA for holes. The OFF current is well below the pA range (100 fA). The three coloured dots mark the 3 operating regions in this configuration: OFF state (red), ON state n-type (yellow) and ON state p-type (green). The inset shows the electrical connections used during the measurement.
