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An investigation into the conversion of In2O3 into InN nanowires.

Papageorgiou P, Zervos M, Othonos A - Nanoscale Res Lett (2011)

Bottom Line: The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In2O3 to InN.We find that the nitridation of In2O3 is effective by using NH3 and H2 or a two-step temperature nitridation process using just NH3 and slower ramp rates.We discuss the nitridation mechanism and its effect on the PL.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanostructured Materials and Devices Laboratory, Department of Mechanical Engineering, Materials Science Group, School of Engineering, University of Cyprus, P,O, Box 20537, Nicosia, 1678, Cyprus. zervos@ucy.ac.cy.

ABSTRACT
Straight In2O3 nanowires (NWs) with diameters of 50 nm and lengths ≥2 μm have been grown on Si(001) via the wet oxidation of In at 850°C using Au as a catalyst. These exhibited clear peaks in the X-ray diffraction corresponding to the body centred cubic crystal structure of In2O3 while the photoluminescence (PL) spectrum at 300 K consisted of two broad peaks, centred around 400 and 550 nm. The post-growth nitridation of In2O3 NWs was systematically investigated by varying the nitridation temperature between 500 and 900°C, flow of NH3 and nitridation times between 1 and 6 h. The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In2O3 to InN. We find that the nitridation of In2O3 is effective by using NH3 and H2 or a two-step temperature nitridation process using just NH3 and slower ramp rates. We discuss the nitridation mechanism and its effect on the PL.

No MeSH data available.


XRD of In2O3 NWs obtained after nitridation at 500 and 600°C for different times as described in Table 1.
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Figure 4: XRD of In2O3 NWs obtained after nitridation at 500 and 600°C for different times as described in Table 1.

Mentions: Again the conversion of In2O3 NWs to InN appears to be incomplete as can be clearly seen from the XRD spectra in Figure 4 where one can observe the presence of In2O3 peaks and just one peak at (101) corresponding to InN. In order to achieve the efficient conversion of In2O3 NWs to InN without eliminating them, we used two different approaches. In the first one, we have carried out post-growth nitridation, which included H2 as shown in Table 1 and in the second approach, we have utilised a two-step temperature nitridation process. The corresponding XRD spectra are shown in Figure 5. As can be seen from the XRD spectra, H2 plays a significant role in the removal of the oxygen and thus all major oxide peaks are eliminated and the conversion to InN is achieved with 40% H2. As already described above, NH3 alone does not promote the efficient conversion of In2O3 NWs into InN at temperatures between 500 and 600°C. This is likely due to the formation of an InN shell around the In2O3, which prevents the diffusion of N into the In2O3 core. However, H2 appears to promote the conversion of In2O3into InN [14].


An investigation into the conversion of In2O3 into InN nanowires.

Papageorgiou P, Zervos M, Othonos A - Nanoscale Res Lett (2011)

XRD of In2O3 NWs obtained after nitridation at 500 and 600°C for different times as described in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211398&req=5

Figure 4: XRD of In2O3 NWs obtained after nitridation at 500 and 600°C for different times as described in Table 1.
Mentions: Again the conversion of In2O3 NWs to InN appears to be incomplete as can be clearly seen from the XRD spectra in Figure 4 where one can observe the presence of In2O3 peaks and just one peak at (101) corresponding to InN. In order to achieve the efficient conversion of In2O3 NWs to InN without eliminating them, we used two different approaches. In the first one, we have carried out post-growth nitridation, which included H2 as shown in Table 1 and in the second approach, we have utilised a two-step temperature nitridation process. The corresponding XRD spectra are shown in Figure 5. As can be seen from the XRD spectra, H2 plays a significant role in the removal of the oxygen and thus all major oxide peaks are eliminated and the conversion to InN is achieved with 40% H2. As already described above, NH3 alone does not promote the efficient conversion of In2O3 NWs into InN at temperatures between 500 and 600°C. This is likely due to the formation of an InN shell around the In2O3, which prevents the diffusion of N into the In2O3 core. However, H2 appears to promote the conversion of In2O3into InN [14].

Bottom Line: The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In2O3 to InN.We find that the nitridation of In2O3 is effective by using NH3 and H2 or a two-step temperature nitridation process using just NH3 and slower ramp rates.We discuss the nitridation mechanism and its effect on the PL.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanostructured Materials and Devices Laboratory, Department of Mechanical Engineering, Materials Science Group, School of Engineering, University of Cyprus, P,O, Box 20537, Nicosia, 1678, Cyprus. zervos@ucy.ac.cy.

ABSTRACT
Straight In2O3 nanowires (NWs) with diameters of 50 nm and lengths ≥2 μm have been grown on Si(001) via the wet oxidation of In at 850°C using Au as a catalyst. These exhibited clear peaks in the X-ray diffraction corresponding to the body centred cubic crystal structure of In2O3 while the photoluminescence (PL) spectrum at 300 K consisted of two broad peaks, centred around 400 and 550 nm. The post-growth nitridation of In2O3 NWs was systematically investigated by varying the nitridation temperature between 500 and 900°C, flow of NH3 and nitridation times between 1 and 6 h. The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In2O3 to InN. We find that the nitridation of In2O3 is effective by using NH3 and H2 or a two-step temperature nitridation process using just NH3 and slower ramp rates. We discuss the nitridation mechanism and its effect on the PL.

No MeSH data available.