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Effect of the Nd content on the structural and photoluminescence properties of silicon-rich silicon dioxide thin films.

Debieu O, Cardin J, Portier X, Gourbilleau F - Nanoscale Res Lett (2011)

Bottom Line: Under non-resonant excitation at 488 nm, our Nd-doped SRSO films simultaneously exhibited PL from Si-np and Nd3+ demonstrating the efficient energy transfer between Si-np and Nd3+ and the sensitizing effect of Si-np.Moreover, the presence of Nd-oxide nanocrystals in the highest Nd-doped sample was established by XRD.It is, therefore, suggested that the Nd clustering, as well as disorder, are responsible for the concentration quenching of the PL of Nd3+.

View Article: PubMed Central - HTML - PubMed

Affiliation: CIMAP, UMR CNRS/CEA/ENSICAEN/UCBN, Ensicaen 6 Bd Maréchal Juin, 14050 Caen Cedex 4, France. fabrice.gourbilleau@ensicaen.fr.

ABSTRACT
In this article, the microstructure and photoluminescence (PL) properties of Nd-doped silicon-rich silicon oxide (SRSO) are reported as a function of the annealing temperature and the Nd concentration. The thin films, which were grown on Si substrates by reactive magnetron co-sputtering, contain the same Si excess as determined by Rutherford backscattering spectrometry. Fourier transform infrared (FTIR) spectra show that a phase separation occurs during the annealing because of the condensation of the Si excess resulting in the formation of silicon nanoparticles (Si-np) as detected by high-resolution transmission electron microscopy and X-ray diffraction (XRD) measurements. Under non-resonant excitation at 488 nm, our Nd-doped SRSO films simultaneously exhibited PL from Si-np and Nd3+ demonstrating the efficient energy transfer between Si-np and Nd3+ and the sensitizing effect of Si-np. Upon increasing the Nd concentration from 0.08 to 4.9 at.%, our samples revealed a progressive quenching of the Nd3+ PL which can be correlated with the concomitant increase of disorder within the host matrix as shown by FTIR experiments. Moreover, the presence of Nd-oxide nanocrystals in the highest Nd-doped sample was established by XRD. It is, therefore, suggested that the Nd clustering, as well as disorder, are responsible for the concentration quenching of the PL of Nd3+.

No MeSH data available.


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FTIR spectrum of the lowest Nd-doped sample as-deposited.
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Figure 1: FTIR spectrum of the lowest Nd-doped sample as-deposited.

Mentions: Figure 1 shows the FTIR spectrum of the lowest Nd-doped sample as-deposited and a fit with eight Gaussian peaks. Several bands characteristic of amorphous SiO2 are observed. The two prominent bands at 1236 (red), and 1052 cm-1 (blue) are assigned to longitudinal optical (LO3) and transverse optical (TO3) phonons of Si-O bonds, respectively. One can notice that these two bands are slightly shifted to lower wavenumbers compared to the stoichiometric positions of a-SiO2 at 1256 and 1076 cm-1, respectively. The TO2, LO2, LO4, and TO4 vibration modes are also present at 810, 820, 1160, and 1200 cm-1, respectively. In addition to Si-O vibration modes, a weak absorption band centered at 880 cm-1 is observed. This peak, which is assigned to Si-H bonds, disappears after annealing because of the hydrogen desorption.


Effect of the Nd content on the structural and photoluminescence properties of silicon-rich silicon dioxide thin films.

Debieu O, Cardin J, Portier X, Gourbilleau F - Nanoscale Res Lett (2011)

FTIR spectrum of the lowest Nd-doped sample as-deposited.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211213&req=5

Figure 1: FTIR spectrum of the lowest Nd-doped sample as-deposited.
Mentions: Figure 1 shows the FTIR spectrum of the lowest Nd-doped sample as-deposited and a fit with eight Gaussian peaks. Several bands characteristic of amorphous SiO2 are observed. The two prominent bands at 1236 (red), and 1052 cm-1 (blue) are assigned to longitudinal optical (LO3) and transverse optical (TO3) phonons of Si-O bonds, respectively. One can notice that these two bands are slightly shifted to lower wavenumbers compared to the stoichiometric positions of a-SiO2 at 1256 and 1076 cm-1, respectively. The TO2, LO2, LO4, and TO4 vibration modes are also present at 810, 820, 1160, and 1200 cm-1, respectively. In addition to Si-O vibration modes, a weak absorption band centered at 880 cm-1 is observed. This peak, which is assigned to Si-H bonds, disappears after annealing because of the hydrogen desorption.

Bottom Line: Under non-resonant excitation at 488 nm, our Nd-doped SRSO films simultaneously exhibited PL from Si-np and Nd3+ demonstrating the efficient energy transfer between Si-np and Nd3+ and the sensitizing effect of Si-np.Moreover, the presence of Nd-oxide nanocrystals in the highest Nd-doped sample was established by XRD.It is, therefore, suggested that the Nd clustering, as well as disorder, are responsible for the concentration quenching of the PL of Nd3+.

View Article: PubMed Central - HTML - PubMed

Affiliation: CIMAP, UMR CNRS/CEA/ENSICAEN/UCBN, Ensicaen 6 Bd Maréchal Juin, 14050 Caen Cedex 4, France. fabrice.gourbilleau@ensicaen.fr.

ABSTRACT
In this article, the microstructure and photoluminescence (PL) properties of Nd-doped silicon-rich silicon oxide (SRSO) are reported as a function of the annealing temperature and the Nd concentration. The thin films, which were grown on Si substrates by reactive magnetron co-sputtering, contain the same Si excess as determined by Rutherford backscattering spectrometry. Fourier transform infrared (FTIR) spectra show that a phase separation occurs during the annealing because of the condensation of the Si excess resulting in the formation of silicon nanoparticles (Si-np) as detected by high-resolution transmission electron microscopy and X-ray diffraction (XRD) measurements. Under non-resonant excitation at 488 nm, our Nd-doped SRSO films simultaneously exhibited PL from Si-np and Nd3+ demonstrating the efficient energy transfer between Si-np and Nd3+ and the sensitizing effect of Si-np. Upon increasing the Nd concentration from 0.08 to 4.9 at.%, our samples revealed a progressive quenching of the Nd3+ PL which can be correlated with the concomitant increase of disorder within the host matrix as shown by FTIR experiments. Moreover, the presence of Nd-oxide nanocrystals in the highest Nd-doped sample was established by XRD. It is, therefore, suggested that the Nd clustering, as well as disorder, are responsible for the concentration quenching of the PL of Nd3+.

No MeSH data available.


Related in: MedlinePlus