Enhanced Electrical Interfaces in Flexible 2D Material Transistors via Liquid Metal and Ionic Liquid Injection.

Abstract

Contact engineering at the semiconductor-electrode and semiconductor-dielectric interfaces is critical to the performance of electronic devices, especially for delicate 2D semiconductors. Here, this study proposes a new paradigm of flexible field-effect transistors featuring solid-liquid hybrid interfaces, in which liquid metal and ionic liquid, confined within microchannels, function as the source/drain electrodes and gate dielectric, respectively. These interfaces provide MoS₂ with undisturbed, atomically smooth electrical contacts, and enable efficient gate control via electric double layers. Benefiting from the inherent softness of liquids and their damage-free processing, Fermi level pinning is significantly mitigated by the liquid metal, achieving a pinning factor |s| = 0.7. Meanwhile, the ionic liquid enables a subthreshold swing of 60.7 mV dec-1, approaching the theoretical thermal limit. Furthermore, our flexible transistors demonstrate multifunctionality as enhanced logic gates, low-voltage inverters, and ultra-high-linearity synaptic devices. This work underscores the promise of liquid-enabled contact strategies for advancing low-power, flexible electronics and soft robotic systems.