Fig. 4: I–V characteristics of two terminal devices based on WZ’ type α-In2Se3 films.
a I–V curve of a Pt/In2Se3/Pt in-plane device with a channel width of 6 µm. Insets show the nominal polarization loop (up) derived from the I–V curve, and the schematical device structure (down). Black arrows indicate the voltage sweeping direction. Blue and red lines are guide to the eyes. b Consecutive I–V sweepings after setting the device by a −6 V and a +6 V triangle voltage pulse. Arrows indicate the voltage scan direction. c I–V curves with various scanning rates. Inset represents the peak voltage Vc as a function of the sweeping frequency, which follows a traditional power low as indicated by red and blue lines. d SKPFM surface potential image of a typical Pt/In2Se3/Pt IP device and the line scans along the black and red dashed lines. e Schematic diagrams for energy bands with polarization pointing to opposite directions. The device can be regarded as two back-to-back diodes in series with a bulk resistance, and FE polarization can alter the Schottky barriers. f The band evolutions of right In2Se3/Pt interface under various positive voltages applied onto the left electrode. g I–V curve of the out-of-plane (OOP) Pt/In2Se3/Si device. The top inset is the enlarged I–V curve with numbered arrows indicating the voltage sweeping sequence, and the bottom inset is a schematic of the OOP device.
