Spontaneous Phase Transition Charge of Liquid Metals\nInduced NH<sub>3</sub> Decomposition To Achieve GaN Nanomaterials\nat Room Temperature

Gallium\nnitride (GaN) is a wide-band gap semiconductor material\nwith excellent optoelectronic performance and stability, which has\nbeen widely used in electronic devices. However, the previous promotion\nand expansion of GaN were limited by harsh manufacturing conditions\nand complex processes. The unique room-temperature liquid-state structure\nand adjustable surface atomic composition of liquid metals present\nan ideal platform for the energy-efficient production of functional\nmaterials. Herein, we propose a strategy for surface atomic low-energy\nmanufacturing of liquid metals based on mechanical friction to achieve\nGaN films. The Ga and In particles were combined and then subjected\nto NH<sub>3</sub> atmosphere. The contact interface between Ga and\nIn particles spontaneously undergoes a liquid-phase transition to\nform liquid metals. The friction charges were generated at the multilevel\ninterfaces from the mixed-phase system, including Ga/In, Ga/eGaIn,\nand In/eGaIn. The microcurrent initiates the breaking of N–H\nbonds in NH<sub>3</sub>. These intermediates reassembled on the liquid\nmetal surface, initiating the deposition and formation of a GaN nanomaterial\nfilm while releasing hydrogen (H<sub>2</sub>). Furthermore, by combining\nthe diversity and adjustability of atoms and gases, this finding provides\na universal, effective, and green manufacturing strategy for functional\nfilms, and is expected to promote the development of mechanical manufacturing\ntechniques.