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Visible and infrared emission from Si/Ge nanowires synthesized by metal-assisted wet etching.

Irrera A, Artoni P, Fioravanti V, Franzò G, Fazio B, Musumeci P, Boninelli S, Impellizzeri G, Terrasi A, Priolo F, Iacona F - Nanoscale Res Lett (2014)

Bottom Line: In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm.NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures.PACS: 61.46.Km; 78.55.-m; 78.67.Lt.

View Article: PubMed Central - HTML - PubMed

Affiliation: IPCF CNR, viale F, Stagno d'Alcontres 37, Faro Superiore, Messina 98158, Italy. irrera@its.me.cnr.it.

ABSTRACT
Multi-quantum well Si/Ge nanowires (NWs) were realized by combining molecular beam epitaxy deposition and metal-assisted wet etching, which is a low-cost technique for the synthesis of extremely dense (about 1011 cm-2) arrays of NWs with a high and controllable aspect ratio. In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm. NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures. We performed a detailed study of the photoluminescence properties of the NWs, with particular attention to the excitation and de-excitation properties as a function of the temperature and of the excitation photon flux, evaluating the excitation cross section and investigating the presence of non-radiative phenomena. PACS: 61.46.Km; 78.55.-m; 78.67.Lt.

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Raman analysis of Si/Ge NWs. Comparison between the Raman spectra of Si/Ge NWs (blue continuous line) and bulk crystalline Si (red dashed line). A fit to the spectrum of Si/Ge NWs gives a diameter mean value of 8.2 ± 1.0 nm.
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Figure 4: Raman analysis of Si/Ge NWs. Comparison between the Raman spectra of Si/Ge NWs (blue continuous line) and bulk crystalline Si (red dashed line). A fit to the spectrum of Si/Ge NWs gives a diameter mean value of 8.2 ± 1.0 nm.

Mentions: Raman measurements were used to estimate the NW mean size. Figure 4 shows the typical asymmetrically broadened Raman peak (solid line), due to the Si-Si stretching mode in optically confined crystalline Si nanostructures, detected on the Si/Ge NWs. The peak appears red shifted with respect to the symmetric and sharper peak typical of bulk crystalline Si at 520 cm−1 (dashed line), reported in the same figure for comparison. The peak was fitted using a phenomenological model developed by Richter [16] and Campbell and Fauchet [17] for strongly confined phonons in nanocrystals and more recently adapted to Si NWs [2,18]. The fit procedure gives a NW diameter of 8.2 ± 1.0 nm.


Visible and infrared emission from Si/Ge nanowires synthesized by metal-assisted wet etching.

Irrera A, Artoni P, Fioravanti V, Franzò G, Fazio B, Musumeci P, Boninelli S, Impellizzeri G, Terrasi A, Priolo F, Iacona F - Nanoscale Res Lett (2014)

Raman analysis of Si/Ge NWs. Comparison between the Raman spectra of Si/Ge NWs (blue continuous line) and bulk crystalline Si (red dashed line). A fit to the spectrum of Si/Ge NWs gives a diameter mean value of 8.2 ± 1.0 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928609&req=5

Figure 4: Raman analysis of Si/Ge NWs. Comparison between the Raman spectra of Si/Ge NWs (blue continuous line) and bulk crystalline Si (red dashed line). A fit to the spectrum of Si/Ge NWs gives a diameter mean value of 8.2 ± 1.0 nm.
Mentions: Raman measurements were used to estimate the NW mean size. Figure 4 shows the typical asymmetrically broadened Raman peak (solid line), due to the Si-Si stretching mode in optically confined crystalline Si nanostructures, detected on the Si/Ge NWs. The peak appears red shifted with respect to the symmetric and sharper peak typical of bulk crystalline Si at 520 cm−1 (dashed line), reported in the same figure for comparison. The peak was fitted using a phenomenological model developed by Richter [16] and Campbell and Fauchet [17] for strongly confined phonons in nanocrystals and more recently adapted to Si NWs [2,18]. The fit procedure gives a NW diameter of 8.2 ± 1.0 nm.

Bottom Line: In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm.NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures.PACS: 61.46.Km; 78.55.-m; 78.67.Lt.

View Article: PubMed Central - HTML - PubMed

Affiliation: IPCF CNR, viale F, Stagno d'Alcontres 37, Faro Superiore, Messina 98158, Italy. irrera@its.me.cnr.it.

ABSTRACT
Multi-quantum well Si/Ge nanowires (NWs) were realized by combining molecular beam epitaxy deposition and metal-assisted wet etching, which is a low-cost technique for the synthesis of extremely dense (about 1011 cm-2) arrays of NWs with a high and controllable aspect ratio. In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm. NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures. We performed a detailed study of the photoluminescence properties of the NWs, with particular attention to the excitation and de-excitation properties as a function of the temperature and of the excitation photon flux, evaluating the excitation cross section and investigating the presence of non-radiative phenomena. PACS: 61.46.Km; 78.55.-m; 78.67.Lt.

No MeSH data available.


Related in: MedlinePlus