A surface-potential-based electrical model for amorphous InGaZnO electric-double-layer transistors with electrolyte insulation

The electric-double-layer transistors (EDLTs) have attracted much attention on achieving ultra-high-density charge accumulation and low operating voltage due to their huge capacitance in electrolyte insulation. A surface-potential-based electric-double-layer (EDL) capacitance and drain current model for amorphous InGaZnO EDLTs is proposed in this paper. It is demonstrated that the EDL capacitance, which includes compact layer and diffuse layer capacitance, is affected not only by the ionic characteristics of the electrolyte, but also by the partial voltage of the gate voltage VGS. The calculated drain current shows good consistency with the reported experimental data. Finally, the effect of the ionic density c and the occupancy of electrolyte capacity on EDL capacitance, surface potential and drain current in the amorphous InGaZnO EDLTs are analyzed with the VGS-dependent EDL capacitance taken into consideration.