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Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid.

Nourmohammadi A, Asadabadi SJ, Yousefi MH, Ghasemzadeh M - Nanoscale Res Lett (2012)

Bottom Line: The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure.Different excitation wavelengths are used to identify most of the details of the subband states.Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Faculty of Science, University of Isfahan, Isfahan, 81746-73441, Iran. a.nourmohammadi@phys.ui.ac.ir.

ABSTRACT
The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

No MeSH data available.


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Fitted photoluminescence emissions of the PAAO membranes. The membranes were prepared after (a) 11, (b) 20, and (c) 40 h of anodizing.
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Figure 5: Fitted photoluminescence emissions of the PAAO membranes. The membranes were prepared after (a) 11, (b) 20, and (c) 40 h of anodizing.

Mentions: Different PL emissions of the samples of Figure 4 are analyzed in Figure 5 in order to evaluate the effect of anodizing time on the subband transitions quantitatively. The analyzed emission spectra of the membranes anodized at 100 V over 11- and 20-h time periods are shown in Figure 5a,b, respectively. Both spectra are composed of five contributive peaks. In Figure 5b, the same emission spectrum of Figure 3a is shown in order to compare the effect of the anodizing time on the subband transitions. The position of all Gaussian emissions of Figure 5b show a rather equal blueshift compared to the membrane of Figure 5a (see for instance peaks 1 and 2 in both figures). In Figure 5a, the maximum emission intensity takes place about 430 nm, which is close to the middle of the blue region. However, the maximum emission intensity of Figure 5b is at 415 nm which is close to the beginning of the blue region. For the membrane which is anodized for 40 h (Figure 5c), a high emission peak is observed at 394 nm which is quite close to the ultraviolet region. This confirms quantitatively widening of the electronic subband gaps due to the oxygen vacancies during a longtime anodizing process.


Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid.

Nourmohammadi A, Asadabadi SJ, Yousefi MH, Ghasemzadeh M - Nanoscale Res Lett (2012)

Fitted photoluminescence emissions of the PAAO membranes. The membranes were prepared after (a) 11, (b) 20, and (c) 40 h of anodizing.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585920&req=5

Figure 5: Fitted photoluminescence emissions of the PAAO membranes. The membranes were prepared after (a) 11, (b) 20, and (c) 40 h of anodizing.
Mentions: Different PL emissions of the samples of Figure 4 are analyzed in Figure 5 in order to evaluate the effect of anodizing time on the subband transitions quantitatively. The analyzed emission spectra of the membranes anodized at 100 V over 11- and 20-h time periods are shown in Figure 5a,b, respectively. Both spectra are composed of five contributive peaks. In Figure 5b, the same emission spectrum of Figure 3a is shown in order to compare the effect of the anodizing time on the subband transitions. The position of all Gaussian emissions of Figure 5b show a rather equal blueshift compared to the membrane of Figure 5a (see for instance peaks 1 and 2 in both figures). In Figure 5a, the maximum emission intensity takes place about 430 nm, which is close to the middle of the blue region. However, the maximum emission intensity of Figure 5b is at 415 nm which is close to the beginning of the blue region. For the membrane which is anodized for 40 h (Figure 5c), a high emission peak is observed at 394 nm which is quite close to the ultraviolet region. This confirms quantitatively widening of the electronic subband gaps due to the oxygen vacancies during a longtime anodizing process.

Bottom Line: The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure.Different excitation wavelengths are used to identify most of the details of the subband states.Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Faculty of Science, University of Isfahan, Isfahan, 81746-73441, Iran. a.nourmohammadi@phys.ui.ac.ir.

ABSTRACT
The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

No MeSH data available.


Related in: MedlinePlus