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Impact of AFM-induced nano-pits in a-Si:H films on silicon crystal growth.

Verveniotis E, Rezek B, Sípek E, Stuchlík J, Ledinský M, Kočka J - Nanoscale Res Lett (2011)

Bottom Line: In this article, the authors show that such local modifications can be used to selectively induce further localized growth of silicon nanocrystals.First, a-Si:H films by plasma-enhanced chemical vapor deposition on nickel/glass substrates are prepared.This is also supported by micro-Raman spectroscopy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics ASCR, Cukrovarnicka 10, 16253, Prague 6, Czech Republic. verven@fzu.cz.

ABSTRACT
Conductive tips in atomic force microscopy (AFM) can be used to localize field-enhanced metal-induced solid-phase crystallization (FE-MISPC) of amorphous silicon (a-Si:H) at room temperature down to nanoscale dimensions. In this article, the authors show that such local modifications can be used to selectively induce further localized growth of silicon nanocrystals. First, a-Si:H films by plasma-enhanced chemical vapor deposition on nickel/glass substrates are prepared. After the FE-MISPC process, yielding both conductive and non-conductive nano-pits in the films, the second silicon layer at the boundary condition of amorphous and microcrystalline growth is deposited. Comparing AFM morphology and current-sensing AFM data on the first and second layers, it is observed that the second deposition changes the morphology and increases the local conductivity of FE-MISPC-induced pits by up to an order of magnitude irrespective of their prior conductivity. This is attributed to the silicon nanocrystals (<100 nm) that tend to nucleate and grow inside the pits. This is also supported by micro-Raman spectroscopy.

No MeSH data available.


Related in: MedlinePlus

Raman spectra of FE-MISPC induced conductive features before and after the second deposition process. The inset shows the topography of the measured area corresponding to the spectrum "after". The spectrum was measured in the central part of the pit. Spectra are normalized to the amorphous band.
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Figure 4: Raman spectra of FE-MISPC induced conductive features before and after the second deposition process. The inset shows the topography of the measured area corresponding to the spectrum "after". The spectrum was measured in the central part of the pit. Spectra are normalized to the amorphous band.

Mentions: Figure 4 shows the micro-Raman spectrum measured on the conductive pit after second deposition (AFM topography is shown in the inset image). The crystalline silicon peak at 521 cm-1 is well resolvable, even though it is superimposed with much more pronounced amorphous band. This is because most of the material in the focus of the Raman is amorphous. Accounting for Raman focus diameter of about 700 nm (objective 100×, λ = 785 nm) and crystalline region diameter of 100 nm, crystalline fraction makes only 2% of the detection area. Raman measurements, before the second deposition on various FE-MISPC-exposed spots, showed only broad amorphous band (typical spectrum shown in Figure 4), obviously because the crystalline phase amount was below the detection threshold.


Impact of AFM-induced nano-pits in a-Si:H films on silicon crystal growth.

Verveniotis E, Rezek B, Sípek E, Stuchlík J, Ledinský M, Kočka J - Nanoscale Res Lett (2011)

Raman spectra of FE-MISPC induced conductive features before and after the second deposition process. The inset shows the topography of the measured area corresponding to the spectrum "after". The spectrum was measured in the central part of the pit. Spectra are normalized to the amorphous band.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211195&req=5

Figure 4: Raman spectra of FE-MISPC induced conductive features before and after the second deposition process. The inset shows the topography of the measured area corresponding to the spectrum "after". The spectrum was measured in the central part of the pit. Spectra are normalized to the amorphous band.
Mentions: Figure 4 shows the micro-Raman spectrum measured on the conductive pit after second deposition (AFM topography is shown in the inset image). The crystalline silicon peak at 521 cm-1 is well resolvable, even though it is superimposed with much more pronounced amorphous band. This is because most of the material in the focus of the Raman is amorphous. Accounting for Raman focus diameter of about 700 nm (objective 100×, λ = 785 nm) and crystalline region diameter of 100 nm, crystalline fraction makes only 2% of the detection area. Raman measurements, before the second deposition on various FE-MISPC-exposed spots, showed only broad amorphous band (typical spectrum shown in Figure 4), obviously because the crystalline phase amount was below the detection threshold.

Bottom Line: In this article, the authors show that such local modifications can be used to selectively induce further localized growth of silicon nanocrystals.First, a-Si:H films by plasma-enhanced chemical vapor deposition on nickel/glass substrates are prepared.This is also supported by micro-Raman spectroscopy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics ASCR, Cukrovarnicka 10, 16253, Prague 6, Czech Republic. verven@fzu.cz.

ABSTRACT
Conductive tips in atomic force microscopy (AFM) can be used to localize field-enhanced metal-induced solid-phase crystallization (FE-MISPC) of amorphous silicon (a-Si:H) at room temperature down to nanoscale dimensions. In this article, the authors show that such local modifications can be used to selectively induce further localized growth of silicon nanocrystals. First, a-Si:H films by plasma-enhanced chemical vapor deposition on nickel/glass substrates are prepared. After the FE-MISPC process, yielding both conductive and non-conductive nano-pits in the films, the second silicon layer at the boundary condition of amorphous and microcrystalline growth is deposited. Comparing AFM morphology and current-sensing AFM data on the first and second layers, it is observed that the second deposition changes the morphology and increases the local conductivity of FE-MISPC-induced pits by up to an order of magnitude irrespective of their prior conductivity. This is attributed to the silicon nanocrystals (<100 nm) that tend to nucleate and grow inside the pits. This is also supported by micro-Raman spectroscopy.

No MeSH data available.


Related in: MedlinePlus