Synthesis of monophase two‐dimensional α‐Si3N4 nanoplatelets via an ionothermal route

Abstract

AbstractMonophase α‐Si3N4 was prepared by a salt melt strategy using Si as a starting material. The results showed that molten salt enhanced the conversion of Si to monophase α‐Si3N4, and some as‐synthesized α‐Si3N4 nanoparticles had a hexagonal platelet morphology. The α‐Si3N4 hexagonal nanoplatelets had an average lateral dimension of about 170 nm and a thickness of about 5.2 nm. The nitridation of Si in molten salt was investigated by a thermal quenching method, and the silicon halide intermediate products were detected by X‐ray photoelectron spectroscopy. Silicon halides possessing higher reactive activity facilitated the nitridation of Si and nucleation of α‐Si3N4. Furthermore, the lattice mismatch between α‐Si3N4 and the salts was calculated, suggesting that the lateral growth of α‐Si3N4 nanoplatelets had been guided by the salt crystal structure. Based on the results, the relevant formation mechanism of α‐Si3N4 nanoplatelets was proposed.