Eutectic Gallium–Indium in Fabricating and Integrating Molecular Devices

Abstract

Molecular electronics and molecular devices based on self-assembled monolayers (SAMs), offer a transformative pathway for next-generation circuits at nanoscale toward ultrahigh integration. A critical challenge lies in fabricating reliable molecular junctions, particularly integrating stable top electrodes without damaging SAMs. Eutectic gallium-indium (EGaIn), a liquid metal alloy, has emerged as a versatile solution, enabling non-invasive, reproducible, and stable top electrodes. This review highlights key EGaIn-based techniques—conical tips, microfluidics, print, and stamping—for fabricating molecular junctions, logic gates, and circuits. The advancement of EGaIn methods gradually address challenges such as contact precision, yield, stability and scalability, enabling the study of charge transport mechanisms and the development of functional molecular devices.