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Long-term oxidization and phase transition of InN nanotextures.

Sarantopoulou E, Kollia Z, Dražic G, Kobe S, Antonakakis NS - Nanoscale Res Lett (2011)

Bottom Line: 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-Ox-Ny (indium oxynitride) phase to a final bi-phase hcp-InN/bcc-In2O3 nanotexture.When the oxidized area exceeds the critical size of 5 nm, the amorphous In-Ox-Ny phase eventually undergoes phase transition via a slow chemical reaction of atomic oxygen with the indium atoms, forming a single bcc In2O3 phase.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635, Greece. esarant@eie.gr.

ABSTRACT
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-Ox-Ny (indium oxynitride) phase to a final bi-phase hcp-InN/bcc-In2O3 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-Ox-Ny oxynitride phase. When the oxidized area exceeds the critical size of 5 nm, the amorphous In-Ox-Ny phase eventually undergoes phase transition via a slow chemical reaction of atomic oxygen with the indium atoms, forming a single bcc In2O3 phase.

No MeSH data available.


Morphology of InN nanostructures grown on Si [100] substrate, indicating coexistence of the crystal line InN, In2O3 and the amorphous oxynitride In-Oy-Nx phases. (a) 5-nm crystal domains (A), 40-nm crystal domains (C), amorphous oxynitride phase (E), boundary between amorphous and crystal phase (F). (b) Crystal cubic In2O3 nanodomains. In the inset, the FFT images are indicated. The crystal In2O3 nanostructure within the circle (B) is 25 nm wide. The In2O3 crystal nanostructures are rotated with respect to each other (D).
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Figure 6: Morphology of InN nanostructures grown on Si [100] substrate, indicating coexistence of the crystal line InN, In2O3 and the amorphous oxynitride In-Oy-Nx phases. (a) 5-nm crystal domains (A), 40-nm crystal domains (C), amorphous oxynitride phase (E), boundary between amorphous and crystal phase (F). (b) Crystal cubic In2O3 nanodomains. In the inset, the FFT images are indicated. The crystal In2O3 nanostructure within the circle (B) is 25 nm wide. The In2O3 crystal nanostructures are rotated with respect to each other (D).

Mentions: After storing the films for 6 months at ambient conditions, the co-existence of crystal In2O3 and amorphous In-Ox-Ny, together with the InN crystal phase is identified. The HRTEM images indicate the superposition of crystal areas of different contrast and parallel Laue levels, shown within the periphery of the circles C1, C2, and A in Figure 5 and 5A and 5C in Figure 6a, respectively. The image of Figure 5 is recorded immediately after the growth of the film, while that of Figure 6 after 6 months. It is likely that these images correspond to the growth of 2D crystal structures on the top of each other forming thus 3D structures. The picture resembles the collection of randomly overlaid coins with aligned heads.


Long-term oxidization and phase transition of InN nanotextures.

Sarantopoulou E, Kollia Z, Dražic G, Kobe S, Antonakakis NS - Nanoscale Res Lett (2011)

Morphology of InN nanostructures grown on Si [100] substrate, indicating coexistence of the crystal line InN, In2O3 and the amorphous oxynitride In-Oy-Nx phases. (a) 5-nm crystal domains (A), 40-nm crystal domains (C), amorphous oxynitride phase (E), boundary between amorphous and crystal phase (F). (b) Crystal cubic In2O3 nanodomains. In the inset, the FFT images are indicated. The crystal In2O3 nanostructure within the circle (B) is 25 nm wide. The In2O3 crystal nanostructures are rotated with respect to each other (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 6: Morphology of InN nanostructures grown on Si [100] substrate, indicating coexistence of the crystal line InN, In2O3 and the amorphous oxynitride In-Oy-Nx phases. (a) 5-nm crystal domains (A), 40-nm crystal domains (C), amorphous oxynitride phase (E), boundary between amorphous and crystal phase (F). (b) Crystal cubic In2O3 nanodomains. In the inset, the FFT images are indicated. The crystal In2O3 nanostructure within the circle (B) is 25 nm wide. The In2O3 crystal nanostructures are rotated with respect to each other (D).
Mentions: After storing the films for 6 months at ambient conditions, the co-existence of crystal In2O3 and amorphous In-Ox-Ny, together with the InN crystal phase is identified. The HRTEM images indicate the superposition of crystal areas of different contrast and parallel Laue levels, shown within the periphery of the circles C1, C2, and A in Figure 5 and 5A and 5C in Figure 6a, respectively. The image of Figure 5 is recorded immediately after the growth of the film, while that of Figure 6 after 6 months. It is likely that these images correspond to the growth of 2D crystal structures on the top of each other forming thus 3D structures. The picture resembles the collection of randomly overlaid coins with aligned heads.

Bottom Line: 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-Ox-Ny (indium oxynitride) phase to a final bi-phase hcp-InN/bcc-In2O3 nanotexture.When the oxidized area exceeds the critical size of 5 nm, the amorphous In-Ox-Ny phase eventually undergoes phase transition via a slow chemical reaction of atomic oxygen with the indium atoms, forming a single bcc In2O3 phase.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635, Greece. esarant@eie.gr.

ABSTRACT
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-Ox-Ny (indium oxynitride) phase to a final bi-phase hcp-InN/bcc-In2O3 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-Ox-Ny oxynitride phase. When the oxidized area exceeds the critical size of 5 nm, the amorphous In-Ox-Ny phase eventually undergoes phase transition via a slow chemical reaction of atomic oxygen with the indium atoms, forming a single bcc In2O3 phase.

No MeSH data available.