Rapid synthesis of Si3N4 dendritic crystals

Si3N4 dendritic crystals with coexisting α and β polymorphs have been synthesized by a rapid metathesis reaction between SiCl4 and slightly excessive NaN3 at an initial reaction temperature of 100 °C. The growth of the branches is perpendicular to the trunks. The formation of the dendrites can be ascribed to the vapor-solid mechanism. Reaction conditions, such as the reaction temperature and the ratio of reagents, are key factors for controlling the synthesis of the branched Si3N4 structures.