Probing the Structural/Electronic Diversity and Thermal Stability of Various Nanocrystalline Powders of Gallium Nitride GaN

Abstract

Nineteen different gallium nitride nanopowders were prepared with four distinct synthesis methods under a wide range of experimental conditions. Variations of synthetic details were aimed at making diverse GaN powders, mainly, from a viewpoint of their structural and thermal stability properties. The supplemental application of powder XRD and 69Ga MAS NMR spectroscopic methods enabled a coherent insight into both the long-range structural order and electronic features, respectively, supporting the specific Knight shift effect displayed in the NMR spectra of the powders. Thermogravimetric measurements under a neutral gas atmosphere were conducted to probe stability ranges of the powders. The combined results support a broad diversity of GaN nanopowders that require supplemental characterization methods to satisfactorily define their complex structural, compositional, and electronic properties evolved during high-temperature syntheses or thermal annealing.