Phase Modulation of Self-Gating in Ionic Liquid-Functionalized InSe Field-Effect Transistors

Abstract

Understanding the Coulomb interactions between two-dimensional (2D) materials and adjacent ions/impurities is essential to realizing 2D material-based hybrid devices. Electrostatic gating via ionic liquids (ILs) has been employed to study the properties of 2D materials. However, the intrinsic interactions between 2D materials and ILs are rarely addressed. This work studies the intersystem Coulomb interactions in IL-functionalized InSe field-effect transistors by displacement current measurements. We uncover a strong self-gating effect that yields a 50-fold enhancement in interfacial capacitance, reaching 550 nF/cm 2 in the maximum. Moreover, we reveal the IL-phase-dependent transport characteristics, including the channel current, carrier mobility, and density, substantiating the self-gating at the InSe/IL interface. The dominance of self-gating in the rubber phase is attributed to the correlation between the intra-and intersystem Coulomb interactions, further confirmed by Raman spectroscopy. This study provides insights into the capacitive coupling at the InSe/IL interface, paving the way to developing liquid/2D material hybrid devices.

Single‐Gate In‐Transistor Readout of Current Superposition and Collapse Utilizing Quantum Tunneling and Ferroelectric Switching

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2D materials-based photodetectors combined with ferroelectrics

“…Another effective solution is ionic liquid gate. When ionic liquid act as a gate, it could provide strong localized electrical fields to extremely tune the behaviors and characteristics of 2D materials [23,24]. Nevertheless, there are some drawbacks of ionic liquids for gate dielectrics, such as corroding 2D materials, slow response time, and volatility.…”

Interfacial electronic properties between PtSe2and 2D metal electrodes: a first-principles simulation

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