Ionic gating is a powerful technique to realize field-effect transistors (FETs) enabling experiments not possible otherwise. So far, ionic gating has relied on the use of top-electrolyte gates, which pose experimental constraints and make device fabrication complex. Promising results obtained recently in FETs based on solid-state electrolytes remain plagued by spurious phenomena of unknown origin, preventing proper transistor operation, and causing limited control and reproducibility. Here we explore a class of solid-state electrolytes for gating (Lithium-ion conducting glass-ceramics, LICGCs), identify the processes responsible for the spurious phenomena and irreproducible behavior,and demonstrate properly functioning transistors exhibiting high density ambipolar operation with gate capacitance of ~20-50 μF/cm2 (depending on the polarity of the accumulated charges). Using two-dimensional semiconducting transition-metal dichalcogenides we demonstrate the ability to implement ionic-gate spectroscopy to determine the semiconducting bandgap, and to accumulate electron densities above 1014 cm−2, resulting in gate-induced superconductivity in MoS2 multilayers. As LICGCs are implemented in a back-gate configuration, they leave the surface of the material exposed, enabling the use of surface-sensitive techniques (such as scanning tunneling microscopy and photoemission spectroscopy) impossible so far in ionic-liquid gated devices. They also allow double ionic gated devices providing independent control of charge density and electric field.
@article{arxiv.2302.11967,
title = {Full control of solid-state electrolytes for electrostatic gating},
author = {Chuanwu Cao and Margherita Melegari and Marc Philippi and Daniil Domaretskiy and Nicolas Ubrig and Ignacio Gutiérrez-Lezama and Alberto F. Morpurgo},
journal= {arXiv preprint arXiv:2302.11967},
year = {2023}
}