Figure 2. Material characterization and basic DC electrical measurements of the ion-modulated memtransistor. a) Schematic of the ion-modulated memtransistor structure, the channel and solid-state electrolyte are composed of niobium oxide (NbOx) and lithium phosphorous oxynitride (LiPON), respectively, and silicon oxide act as the passivation layer to keep the electrolyte from oxygen and moisture. b) Optical microscope of ion-modulated memtransistor. c) the cross-sectional TEM image of the central part within the device. d) Elemental mapping of the materials in the device for O, P, N, Nb, Si, Ti, and Au, respectively. e) The line scan EDS of the device cross-section, which corresponds to the red arrow in d). f) Crystal structure of lithium phosphate is composed mainly of (PO4)3- tetrahedrons, and lithium ions that are closely bonded to oxygen atoms. In the right part,the P-N and P=N bonds are formed when the nitrogen atoms are doped in Li(PO4)3 crystal. g) Transfer curves of the ion-modulated memtransistor with gate bias swept from -6 V to 4 V at the sweeping rate of 0.53 V/s, which exhibiting counterclockwise hysteresis and the average on/off ratio at 0 V gate bias is approximately 125, the corresponding drain current Id is monitored by applying small 0.1 V DC bias at the drain terminal. The grey lines represent the results of thirty continuous DC sweeps, and the red line represents the average value of these curves. h) Statistical data of drain current Id at the on-state or off-state within thirty DC cycles. i) Leakage currents(Ig) variation corresponding to the DC sweeps in g) show the maximum is below 800 pA, which can help reduce energy cost when programming the device. Transfer curves at different sweeping dynamic ranges. j) and sweeping rate k), the drain-source bias is still kept at 0.1 V.