Lithium-ion electrolytic substrates for sub-1V high-performance transition metal dichalcogenide transistors and amplifiers

Md Hasibul Alam,Deepyanti Taneja,Zifan Xu,Deji Akinwande,Sanjay K Banerjee,Sayema Chowdhury,Zhanzhi Jiang,Keji Lai,Maria Helena Braga

doi:10.1038/s41467-020-17006-w

Md Hasibul Alam, Deepyanti Taneja + Show 7 more

Open Access

https://doi.org/10.1038/s41467-020-17006-w

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Abstract

Electrostatic gating of two-dimensional (2D) materials with ionic liquids (ILs), leading to the accumulation of high surface charge carrier densities, has been often exploited in 2D devices. However, the intrinsic liquid nature of ILs, their sensitivity to humidity, and the stress induced in frozen liquids inhibit ILs from constituting an ideal platform for electrostatic gating. Here we report a lithium-ion solid electrolyte substrate, demonstrating its application in high-performance back-gated n-type MoS2 and p-type WSe2 transistors with sub-threshold values approaching the ideal limit of 60 mV/dec and complementary inverter amplifier gain of 34, the highest among comparable amplifiers. Remarkably, these outstanding values were obtained under 1 V power supply. Microscopic studies of the transistor channel using microwave impedance microscopy reveal a homogeneous channel formation, indicative of a smooth interface between the TMD and underlying electrolytic substrate. These results establish lithium-ion substrates as a promising alternative to ILs for advanced thin-film devices.

Highlights

Electrostatic gating of two-dimensional (2D) materials with ionic liquids (ILs), leading to the accumulation of high surface charge carrier densities, has been often exploited in 2D devices
When a positive bias is applied on the gate electrode, positive mobile ions in the electrolyte get repelled from the GE interface, leaving a layer of negatively charged counter-ions at the interface, thereby forming the GE electric double layers (EDLs) to realign the Fermi levels of gate electrode and electrolyte
We systematically investigate the transport properties of both n-type (MoS2) and p-type (WSe2) transition metal dichalcogenide (TMD) backgated transistors fabricated on Li-ion glass substrate, which works both as the gate dielectric and the supporting substrate

Summary

Introduction

Electrostatic gating of two-dimensional (2D) materials with ionic liquids (ILs), leading to the accumulation of high surface charge carrier densities, has been often exploited in 2D devices. A 3D drawing of a prototypical Li-ion glass EDLT is shown in Supplementary Fig. 2, where silver coating is used as the back-gate metal.

Results

Conclusion