Composition and optical property controlled in In2O3/W2N nanostructure composites by nitrogen plasma assisted in-situ thermal annealing

In2O3/W2N nanostructure composites were grown by nitrogen plasma assisted in-situ thermal annealing at different hot-filament temperatures, Tf. The in-situ thermal annealing changes the as-grown In2O3 nanostructure to In2O3/W2N nanostructure composite with decreasing the grain size from 200 to 300 nm to ~ 100 nm. The optical spectroscopy results indicate that the optical energy gap of the nanostructure composites (3.7-2.7 eV) can be effectively tailored by monotonically increasing the W2N incorporation. The formation of W2N is attributed to the high energetic ion bombardment of N adatoms and incorporation of W adatoms. Furthermore, the effects of the filament temperature, Tf on the compositions in relation with the optical properties of the nanostructure composite are discussed.