Synthesis of Wurtzite-Type InN Crystals by Low-Temperature Nitridation of LiInO2 Using NaNH2 Flux

Nitridation of oxides above 500 degrees C is a conventional route for the synthesis of various oxynitrides and nitrides. However, this technique has the disadvantages of requiring a high temperature to break the strong metal and oxygen bonds and of low utilization efficiency of nitrogen sources such as toxic ammonia. Here, we show a simple low-temperature synthesis of InN nanocrystals via the nitridation of LiInO2 by NaNH2 flux at 240 degrees C in a Teflon-lined autoclave. The NaNH2 flux converted irregular-shaped LiInO2 powder to 50-300 nm InN nanocrystals with well-developed facets. The product crystallized in the hexagonal wurtzite structure with lattice parameters of a = 3.545 angstrom and c = 5.717 angstrom. Lithium in the starting oxide was found to be essential for this low-temperature nitridation.