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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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PL properties of Si/Ge NWs as a function of temperature. (a) PL spectra in the IR region of Si/Ge NWs from 11 K to room temperature. (b) PL time-decay curves measured at 1,220 nm and at temperatures in the 11- to 80-K range. All measurements were performed with a photon flux of 3.1 × 1020 cm−2 · s−1.
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Figure 6: PL properties of Si/Ge NWs as a function of temperature. (a) PL spectra in the IR region of Si/Ge NWs from 11 K to room temperature. (b) PL time-decay curves measured at 1,220 nm and at temperatures in the 11- to 80-K range. All measurements were performed with a photon flux of 3.1 × 1020 cm−2 · s−1.

Mentions: Since the properties of the Si-related PL signal observed in Si/Ge NWs tightly resemble those found in pure Si NWs [2,12], in the rest of the work, we mainly focused our attention on the Ge-related emission. In particular, we studied in detail the IR PL emission as a function of the temperature, as reported in Figure 6a. We observed that by decreasing the temperature, the PL intensity monotonically increases, due to a reduced efficiency of non-radiative phenomena. Furthermore, it can be noticed that the PL emission exhibits a blueshift toward shorter wavelengths by decreasing temperature, in agreement with the well-known dependence of the Ge bandgap on temperature.


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)

PL properties of Si/Ge NWs as a function of temperature. (a) PL spectra in the IR region of Si/Ge NWs from 11 K to room temperature. (b) PL time-decay curves measured at 1,220 nm and at temperatures in the 11- to 80-K range. All measurements were performed with a photon flux of 3.1 × 1020 cm−2 · s−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: PL properties of Si/Ge NWs as a function of temperature. (a) PL spectra in the IR region of Si/Ge NWs from 11 K to room temperature. (b) PL time-decay curves measured at 1,220 nm and at temperatures in the 11- to 80-K range. All measurements were performed with a photon flux of 3.1 × 1020 cm−2 · s−1.
Mentions: Since the properties of the Si-related PL signal observed in Si/Ge NWs tightly resemble those found in pure Si NWs [2,12], in the rest of the work, we mainly focused our attention on the Ge-related emission. In particular, we studied in detail the IR PL emission as a function of the temperature, as reported in Figure 6a. We observed that by decreasing the temperature, the PL intensity monotonically increases, due to a reduced efficiency of non-radiative phenomena. Furthermore, it can be noticed that the PL emission exhibits a blueshift toward shorter wavelengths by decreasing temperature, in agreement with the well-known dependence of the Ge bandgap on temperature.

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