Novel electronic devices using ionic liquid-gated 2D nanomaterials

Published : 15 July 2019

Two-dimensional van der Waals nanomaterials constitute an extremely active research field. Field-effect transistors (FETs) can be built with a 2D semiconductor channel (e.g., MoS2) gated using an ionic liquid (IL) electrolyte in a configuration called an IL-FET. ILs are molten salts at room temperature. Many ILs are (electro)chemically stable and non-volatile thus safe. In IL-FETs the electrostatic field from the interfacial layering of ions induces doping on the 2D semiconductor by stabilizing a high density of charge carriers. Besides the logic functions, components with similar IL/2D-material interfaces can operate as capacitors or sensors.

Research so far has not paid enough attention to choosing or designing the electrolyte. This thesis takes place in the frame of the LIQUI2D project funded by the French ANR aiming at rationalizing the design of ILs for this specific task by uniquely coupling theoretical calculations and experiments.

The main goal of this work is to fabricate and characterize IL-FETs to demonstrate the capabilities of this technology. The starting point of this work will consist in selecting a few ILs, based on theoretical results obtained in the course of the LIQUI2D project. The IL/2D material interface will be characterized using mainly atomic force microscopy (AFM) in liquid environment (ENS Lyon), x-ray photoelectron spectroscopy (XPS) and electrochemical impedance measurements (at CEA Grenoble). The most promising ILs will be implemented in test devices fabricated by the student in the clean-room facilities at CEA Grenoble.

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