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Efficient visible luminescence of nanocrystalline silicon prepared from amorphous silicon films by thermal annealing and stain etching.

Timoshenko VY, Gonchar KA, Mirgorodskiy IV, Maslova NE, Nikulin VE, Mussabek GK, Taurbaev YT, Svanbayev EA, Taurbaev TI - Nanoscale Res Lett (2011)

Bottom Line: In contrast to as-deposited a-Si:H films, the nc-Si films after stain etching exhibited efficient photoluminescence in the spectral range of 600 to 950 nm at room temperature.The photoluminescence intensity and lifetimes of the stain etched nc-Si films were similar to those for conventional porous Si formed by electrochemical etching.The obtained results indicate new possibilities to prepare luminescent thin films for Si-based optoelectronics.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia. timoshen@phys.msu.ru.

ABSTRACT
Films of nanocrystalline silicon (nc-Si) were prepared from hydrogenated amorphous silicon (a-Si:H) by using rapid thermal annealing. The formed nc-Si films were subjected to stain etching in hydrofluoric acid solutions in order to passivate surfaces of nc-Si. The optical reflectance spectroscopy revealed the nc-Si formation as well as the high optical quality of the formed films. The Raman scattering spectroscopy was used to estimate the mean size and volume fraction of nc-Si in the annealed films, which were about 4 to 8 nm and 44 to 90%, respectively, depending on the annealing regime. In contrast to as-deposited a-Si:H films, the nc-Si films after stain etching exhibited efficient photoluminescence in the spectral range of 600 to 950 nm at room temperature. The photoluminescence intensity and lifetimes of the stain etched nc-Si films were similar to those for conventional porous Si formed by electrochemical etching. The obtained results indicate new possibilities to prepare luminescent thin films for Si-based optoelectronics.

No MeSH data available.


Normalized Raman scattering spectra of a-Si:H film (circles) and samples #1 (triangles), #2 (squares), and #3 (solid line).
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Figure 1: Normalized Raman scattering spectra of a-Si:H film (circles) and samples #1 (triangles), #2 (squares), and #3 (solid line).

Mentions: Figure 1 shows the Raman scattering spectra of as-deposited a-Si:H film and the annealed ones. The Raman spectrum of a-Si:H is represented by a broad line centered at 480 cm-1, which is typical for amorphous Si. The Raman spectra of the prepared nc-Si films exhibit a maximum at 513 to 519 cm-1, which is shifted to low frequency range in respect to the peak of c-Si substrate (520.5 cm-1). The shift is usually attributed to the phonon confinement in nc-Si [7]. The size of nc-Si and volume fraction to amorphous Si were estimated from the Raman spectra by using a method reported in ref. [8]. The results shown in Table 1 demonstrate that the RTA treatment with longer duration induced formation of nc-Si with larger mean size and volume fraction. Note, that the FA treatment for 30 min resulted in almost complete crystallization with the nc-Si size of about 8 nm.


Efficient visible luminescence of nanocrystalline silicon prepared from amorphous silicon films by thermal annealing and stain etching.

Timoshenko VY, Gonchar KA, Mirgorodskiy IV, Maslova NE, Nikulin VE, Mussabek GK, Taurbaev YT, Svanbayev EA, Taurbaev TI - Nanoscale Res Lett (2011)

Normalized Raman scattering spectra of a-Si:H film (circles) and samples #1 (triangles), #2 (squares), and #3 (solid line).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211438&req=5

Figure 1: Normalized Raman scattering spectra of a-Si:H film (circles) and samples #1 (triangles), #2 (squares), and #3 (solid line).
Mentions: Figure 1 shows the Raman scattering spectra of as-deposited a-Si:H film and the annealed ones. The Raman spectrum of a-Si:H is represented by a broad line centered at 480 cm-1, which is typical for amorphous Si. The Raman spectra of the prepared nc-Si films exhibit a maximum at 513 to 519 cm-1, which is shifted to low frequency range in respect to the peak of c-Si substrate (520.5 cm-1). The shift is usually attributed to the phonon confinement in nc-Si [7]. The size of nc-Si and volume fraction to amorphous Si were estimated from the Raman spectra by using a method reported in ref. [8]. The results shown in Table 1 demonstrate that the RTA treatment with longer duration induced formation of nc-Si with larger mean size and volume fraction. Note, that the FA treatment for 30 min resulted in almost complete crystallization with the nc-Si size of about 8 nm.

Bottom Line: In contrast to as-deposited a-Si:H films, the nc-Si films after stain etching exhibited efficient photoluminescence in the spectral range of 600 to 950 nm at room temperature.The photoluminescence intensity and lifetimes of the stain etched nc-Si films were similar to those for conventional porous Si formed by electrochemical etching.The obtained results indicate new possibilities to prepare luminescent thin films for Si-based optoelectronics.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia. timoshen@phys.msu.ru.

ABSTRACT
Films of nanocrystalline silicon (nc-Si) were prepared from hydrogenated amorphous silicon (a-Si:H) by using rapid thermal annealing. The formed nc-Si films were subjected to stain etching in hydrofluoric acid solutions in order to passivate surfaces of nc-Si. The optical reflectance spectroscopy revealed the nc-Si formation as well as the high optical quality of the formed films. The Raman scattering spectroscopy was used to estimate the mean size and volume fraction of nc-Si in the annealed films, which were about 4 to 8 nm and 44 to 90%, respectively, depending on the annealing regime. In contrast to as-deposited a-Si:H films, the nc-Si films after stain etching exhibited efficient photoluminescence in the spectral range of 600 to 950 nm at room temperature. The photoluminescence intensity and lifetimes of the stain etched nc-Si films were similar to those for conventional porous Si formed by electrochemical etching. The obtained results indicate new possibilities to prepare luminescent thin films for Si-based optoelectronics.

No MeSH data available.