Phase Modulation of Self-Gating in Ionic Liquid-Functionalized InSe Field-Effect Transistors
Journal
Nano letters
Journal Volume
22
Journal Issue
6
Pages
2270
Date Issued
2022-03-23
Author(s)
Cheng, Chih-Yi
Pai, Wei-Liang
Chen, Yi-Hsun
Paylaga, Naomi Tabudlong
Wu, Pin-Yun
Chou, Fang-Cheng
Sankar, Raman
Fuhrer, Michael S
Chen, Shao-Yu
Wang, Wei-Hua
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/cm2 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.
Subjects
InSe
field-effect transistor
intersystem Coulomb interaction
ionic liquid
long-range Coulomb scattering
self-gating
Publisher
AMER CHEMICAL SOC
Type
journal article