Long-term oxidization and phase transition of InN nanotextures

The long-term (6 months) oxidization of hcp-InN (wurtzite, InN-w) nanostructures (crystalline/amorphous) synthesized on Si [100] substrates is analyzed. The densely packed layers of InN-w nanostructures (5-40 nm) are shown to be oxidized by atmospheric oxygen via the formation of an intermediate amorphous In-O(x)-N(y )(indium oxynitride) phase to a final bi-phase hcp-InN/bcc-In(2)O(3 )nanotexture. High-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy and selected area electron diffraction are used to identify amorphous In-O(x)-N(y )oxynitride phase. When the oxidized area exceeds the critical size of 5 nm, the amorphous In-O(x)-N(y )phase eventually undergoes phase transition via a slow chemical reaction of atomic oxygen with the indium atoms, forming a single bcc In(2)O(3 )phase.