A liquid metal reaction environment for the room-temperature synthesis of atomically thin metal oxides

Abstract

Two-dimensional (2D) oxides have a wide variety of applications in electronics and other technologies. However, many oxides are not easy to synthesize as 2D materials through conventional methods.We used nontoxic eutectic gallium-based alloys as a reaction solvent and co-alloyed desired metals into the melt. On the basis of thermodynamic considerations, we predicted the composition of the self-limiting interfacial oxide.We isolated the surface oxide as a 2D layer, either on substrates or in suspension.This enabled us to produce extremely thin subnanometer layers of HfO2, Al2O3, andGd2O3.The liquid metal-based reaction route can be used to create 2D materials that were previously inaccessible with preexisting methods.The work introduces room-temperature liquid metals as a reaction environment for the synthesis of oxide nanomaterials with low dimensionality.