The Evolution of Synthetic Techniques for Nitride Materials

Nitride compounds have important technological applications, from ceramics and refractory materials to semiconducting perovskites for solar cells. Despite their wide use, the synthesis of nitride materials is usually more challenging than that of most other materials. Although nitrogen gas is an abundant nitrogen source, its inertness is the main obstacle in the synthesis of nitrides. Breaking the N₂ molecule apart and reacting it with other elements takes a lot of energy, normally in the form of heat. At the same time, excessive heating leads to entropy driven decomposition of the product material back to N₂ gas and the metal, presenting a distinct synthetic challenge as compared to other classes of solid-state inorganic materials. This presentation will show how this issue has been overcome in the past and the development of new synthetic pathways to stabilize nitrogen-rich nitrides. We will begin by discussing direct reactions between nitrogen or ammonia with metals at higher temperatures and their evolution to more sophisticated high pressure and physical vapor deposition reactions.