Gallium nitride formation in liquid metal sonication

Abstract

With growing research interest in liquid metals, such as Ga and Ga-based alloys, understanding their behaviours at reduced dimensions is becoming of more fundamental significance, especially for exploiting their properties in a variety of applications. Mechanical sonication is a common technique used for micronising bulk liquid metals into smaller sized particles. One distinct characteristic of Ga and Ga-based liquid metal alloy particles, micronised via sonication, is the formation of native oxygen species such as GaOOH and Ga₂O₃. However, the nitridation of these particles has not been reported. In this work, we demonstrate a room temperature nitridation process during the micronisation of eutectic Ga–In alloy (EGaIn). Characterisations reveal that the sonication in the N-containing precursors of PVP and N₂ results in the formation of GaN within the GaOOH crystallites that separate themselves from the bulk of EGaIn during sonication. As a model example of the applicability of such particles, low-detection-limit biosensing by photoluminescence of the obtained particles is demonstrated. The work shows a room temperature pathway for the creation of GaN that can be further investigated, expanded upon, and implemented for different future applications.