Mechanochemical route to the synthesis of nanostructured Aluminium nitride

Abstract

Hexagonal Aluminium nitride (h-AlN) is an important wide-bandgap semiconductor material which<br><br>is conventionally fabricated by high temperature carbothermal reduction of alumina under toxic<br><br>ammonia atmosphere. Here we report a simple, low cost and potentially scalable mechanochemical<br><br>procedure for the green synthesis of nanostructured h-AlN from a powder mixture of Aluminium and<br><br>melamine precursors. A combination of experimental and theoretical techniques has been employed<br><br>to provide comprehensive mechanistic insights on the reactivity of melamine, solid state metalorganic<br><br>interactions and the structural transformation of Al to h-AlN under non-equilibrium ball milling<br><br>conditions. The results reveal that melamine is adsorbed through the amine groups on the Aluminium<br><br>surface due to the long-range van der Waals forces. The high energy provided by milling leads to the<br><br>deammoniation of melamine at the initial stages followed by the polymerization and formation of<br><br>a carbon nitride network, by the decomposition of the amine groups and, finally, by the subsequent<br><br>diffusion of nitrogen into the Aluminium structure to form h-AlN.