(166s) Structure and Dynamic Property of Electric Double Layer in Ionic-Liquid-Gated Transistor: The Anatomy of Enhanced Gating Performance

Ionic-liquid-gated electric double layer transistors (IL-gated EDLTs), in which the ultrahigh carrier density at semiconductor surface could be achieved by EDL formed by ILs, are attracting growing research interests. Since the interfacial properties of EDL greatly affect the performance of IL-gated EDLTs, understanding the underlying mechanisms is of great significance for designing EDLTs with prominent performance.

In this poster, using molecular dynamics (MD) simulations, the interfacial structures and dynamic properties of EDL formed by different ILs were analyzed. Our previous work shows that during gating process, the more homogeneous electric field-induced charge distribution at semiconductor surface would result in the higher electrical conductance of semiconductor.^[1] By comparing the ionic liquids with different cation types, we found that the type of cation functional group has a great impact on the homogeneity of charge distribution at semiconductor surface, and the conductivity of semiconductor is finally determined by both the homogeneity of charge distribution and the capacitance. Besides the static properties, we found that by adding organic solvent, both the response speed of IL at semiconductor surface and the homogeneity of semiconductor surface charge distribution could be significantly improved, which means that the dynamic and static gating performance of IL-gated EDLTs could be improved simultaneously.^[2] Moreover, the microscopic properties obtained by MD simulations were successfully bridged with macroscopic characteristics of IL-gated EDLTs by resistant network method. Overall, our findings provide both new concepts and modeling techniques for IL-gated EDLTs.

[1] Zhao W, Bi S, Balke N, Rack PD, Ward TZ, Kalinin SV, Dai S, Feng G. Understanding Electric Double-Layer Gating Based on Ionic Liquids: from Nanoscale to Macroscale. ACS Applied Materials & Interfaces. 2018; 10:43211-43218.

[2] Zhao W, Bi S, Zhang C, Rack PD, Feng G. Adding Solvent into Ionic-Liquid-Gated Transistor: The Anatomy of Enhanced Gating Performance. Submitted.