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Synthesis of long group IV semiconductor nanowires by molecular beam epitaxy.

Xu T, Sulerzycki J, Nys JP, Patriarche G, Grandidier B, Stiévenard D - Nanoscale Res Lett (2011)

Bottom Line: Structural studies of both types of NWs performed with electron microscopies reveal a marked difference between the roughnesses of their respective sidewalls.As the investigation of their length dependence on their diameter indicates that the growth of the NWs predominantly proceeds through the diffusion of adatoms from the substrate up along the sidewalls, difference in the sidewall roughness qualitatively explains the length variation measured between both types of NWs.The formation of atomically flat {111} sidewalls on the <110>-oriented Ge NWs accounts for a larger diffusion length.

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Affiliation: Département ISEN, Institut d'Electronique, de Microélectronique et de Nanotechnologie, IEMN (CNRS, UMR 8520), 41 bd Vauban, 59046 Lille Cedex, France. bruno.grandidier@isen.fr.

ABSTRACT
We report the growth of Si and Ge nanowires (NWs) on a Si(111) surface by molecular beam epitaxy. While Si NWs grow perpendicular to the surface, two types of growth axes are found for the Ge NWs. Structural studies of both types of NWs performed with electron microscopies reveal a marked difference between the roughnesses of their respective sidewalls. As the investigation of their length dependence on their diameter indicates that the growth of the NWs predominantly proceeds through the diffusion of adatoms from the substrate up along the sidewalls, difference in the sidewall roughness qualitatively explains the length variation measured between both types of NWs. The formation of atomically flat {111} sidewalls on the <110>-oriented Ge NWs accounts for a larger diffusion length.

No MeSH data available.


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SEM images of (a) Si NWs and (b) Ge NWs grown on a Si(111) surface by MBE. The orientations of the NWs are indicated in the SEM images. The growth times were 2 and 1 h for the Si and Ge NWs, respectively. The scale bars correspond to 400 nm.
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Figure 2: SEM images of (a) Si NWs and (b) Ge NWs grown on a Si(111) surface by MBE. The orientations of the NWs are indicated in the SEM images. The growth times were 2 and 1 h for the Si and Ge NWs, respectively. The scale bars correspond to 400 nm.

Mentions: Tilted views of the post-growth Si(111) surfaces are shown in Figure 2. When Si is sublimated, the majority of the Si NWS are found to be perpendicular to the Si(111) surface (Figure 2a). Their growth axis is thus along the [111] direction, in agreement with previous observations [4,5]. In contrast, the growth of Ge NWs leads to two different kinds of growth directions (Figure 2b). The shortest NWs usually show the Au seed particle just above the overgrown Ge film. These NWs appear normal to the surface when observed in top view SEM images such as the one shown in the inset of Figure 3. They thus grow along the [111] direction, likewise the Si NWs. As for the second type of Ge NWs, these NWs are much longer and point at 54.7° from the surface plane. In the top view SEM image of Figure 3, these inclined Ge NWs are found to grow along three different directions only. When projected in the (111) surface plane, the directions make an angle of 60°. Therefore, these Ge NWs are oriented along one of the equivalent <110> directions, in agreement with the growth of <110>-oriented Ge NWs obtained on the Ge(111) surface by MBE [7].


Synthesis of long group IV semiconductor nanowires by molecular beam epitaxy.

Xu T, Sulerzycki J, Nys JP, Patriarche G, Grandidier B, Stiévenard D - Nanoscale Res Lett (2011)

SEM images of (a) Si NWs and (b) Ge NWs grown on a Si(111) surface by MBE. The orientations of the NWs are indicated in the SEM images. The growth times were 2 and 1 h for the Si and Ge NWs, respectively. The scale bars correspond to 400 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211158&req=5

Figure 2: SEM images of (a) Si NWs and (b) Ge NWs grown on a Si(111) surface by MBE. The orientations of the NWs are indicated in the SEM images. The growth times were 2 and 1 h for the Si and Ge NWs, respectively. The scale bars correspond to 400 nm.
Mentions: Tilted views of the post-growth Si(111) surfaces are shown in Figure 2. When Si is sublimated, the majority of the Si NWS are found to be perpendicular to the Si(111) surface (Figure 2a). Their growth axis is thus along the [111] direction, in agreement with previous observations [4,5]. In contrast, the growth of Ge NWs leads to two different kinds of growth directions (Figure 2b). The shortest NWs usually show the Au seed particle just above the overgrown Ge film. These NWs appear normal to the surface when observed in top view SEM images such as the one shown in the inset of Figure 3. They thus grow along the [111] direction, likewise the Si NWs. As for the second type of Ge NWs, these NWs are much longer and point at 54.7° from the surface plane. In the top view SEM image of Figure 3, these inclined Ge NWs are found to grow along three different directions only. When projected in the (111) surface plane, the directions make an angle of 60°. Therefore, these Ge NWs are oriented along one of the equivalent <110> directions, in agreement with the growth of <110>-oriented Ge NWs obtained on the Ge(111) surface by MBE [7].

Bottom Line: Structural studies of both types of NWs performed with electron microscopies reveal a marked difference between the roughnesses of their respective sidewalls.As the investigation of their length dependence on their diameter indicates that the growth of the NWs predominantly proceeds through the diffusion of adatoms from the substrate up along the sidewalls, difference in the sidewall roughness qualitatively explains the length variation measured between both types of NWs.The formation of atomically flat {111} sidewalls on the <110>-oriented Ge NWs accounts for a larger diffusion length.

View Article: PubMed Central - HTML - PubMed

Affiliation: Département ISEN, Institut d'Electronique, de Microélectronique et de Nanotechnologie, IEMN (CNRS, UMR 8520), 41 bd Vauban, 59046 Lille Cedex, France. bruno.grandidier@isen.fr.

ABSTRACT
We report the growth of Si and Ge nanowires (NWs) on a Si(111) surface by molecular beam epitaxy. While Si NWs grow perpendicular to the surface, two types of growth axes are found for the Ge NWs. Structural studies of both types of NWs performed with electron microscopies reveal a marked difference between the roughnesses of their respective sidewalls. As the investigation of their length dependence on their diameter indicates that the growth of the NWs predominantly proceeds through the diffusion of adatoms from the substrate up along the sidewalls, difference in the sidewall roughness qualitatively explains the length variation measured between both types of NWs. The formation of atomically flat {111} sidewalls on the <110>-oriented Ge NWs accounts for a larger diffusion length.

No MeSH data available.


Related in: MedlinePlus