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A promising routine to fabricate GeSi nanowires via self-assembly on miscut Si (001) substrates.

Zhong Z, Gong H, Ma Y, Fan Y, Jiang Z - Nanoscale Res Lett (2011)

Bottom Line: These results proposed that the formation of the nanowire was energetically driven under growth kinetic assistance.Three-dimensionally self-assembled GeSi nanowires were first realized via multilayer Ge growth separated with Si spacers.These GeSi nanowires were readily embedded in Si matrix and compatible with the sophisticated Si technology, which suggested a feasible strategy to fabricate nanowires for fundamental studies and a wide variety of applications.PACS: 81.07.Gf, 81.16.Dn, 68.65.-k, 68.37.Ps.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Handan Str, 220, Shanghai 200433, China. zhenyangz@fudan.edu.cn.

ABSTRACT
: Very small and compactly arranged GeSi nanowires could self-assembled on vicinal Si (001) substrates with ~8° off toward ⟨110⟩ during Ge deposition. The nanowires were all oriented along the miscut direction. The small ration of height over width of the nanowire indicated that the nanowires were bordered partly with {1 0 5} facets. These self-assembled small nanowires were remarkably influenced by the growth conditions and the miscut angle of substrates in comparison with large dome-like islands obtained after sufficient Ge deposition. These results proposed that the formation of the nanowire was energetically driven under growth kinetic assistance. Three-dimensionally self-assembled GeSi nanowires were first realized via multilayer Ge growth separated with Si spacers. These GeSi nanowires were readily embedded in Si matrix and compatible with the sophisticated Si technology, which suggested a feasible strategy to fabricate nanowires for fundamental studies and a wide variety of applications.PACS: 81.07.Gf, 81.16.Dn, 68.65.-k, 68.37.Ps.

No MeSH data available.


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AFM image (1 × 1 μm2) of GeSi nanowires after 0.8 nm Ge deposition on a vicinal Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The black arrow indicates the miscut direction. The inset shows the height profile along the white line in the figure.
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Figure 1: AFM image (1 × 1 μm2) of GeSi nanowires after 0.8 nm Ge deposition on a vicinal Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The black arrow indicates the miscut direction. The inset shows the height profile along the white line in the figure.

Mentions: Figure 1 showed the surface morphology after 0.8 nm Ge deposition on a Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The compact GeSi nanowires were clearly demonstrated. The nanowires were found to be oriented along the miscut direction of ⟨110⟩, as denoted by a black arrow in the figure. This result was consistent with previous ones [20,21]. The height profile along the white line in the figure was shown in the inset of figure, which clearly exhibited the height and the width of the nanowires. The statistical analyses of the height and the width of the GeSi nanowires were 0.84 nm (± 0.28 nm) and 25.2 nm (± 6.41 nm), respectively. The small ratio of height over width of the nanowires demonstrated that these nanowires were much smaller than the GeSi nanowires of lower Ge composition [21]. This is mainly attributed to the high Ge content in the present nanowires with a large misfit strain. It has been found that the sidewalls of such nanowires were mainly composed of {1 0 5} facets [20,21]. However, in our cases, the ratio of height over width of the present nanowires was considerably smaller than that (~0.07) of the nanowires only composed of {1 0 5} facets. Considering {1 0 5} to be energetically favorable facets [23], we proposed that the sidewalls of the present nanowires were partly composed of {1 0 5} facets and others, which can not be distinguished due to the limitation of the resolution of AFM. This different result was attributed to the growth kinetic limitation at the low growth temperature and the high growth rate. Furthermore, the formation of such small nanowires was more energetically favorable than the layer-by-layer growth during Ge deposition on vicinal substrates after a critical thickness [20]. These self-assembled GeSi nanowires on miscut Si (001) substrates was different from that on very-high-index Si (hkl) substrates, where the GeSi nanowires were along the grooves composed of hill-and-valley structure [16].


A promising routine to fabricate GeSi nanowires via self-assembly on miscut Si (001) substrates.

Zhong Z, Gong H, Ma Y, Fan Y, Jiang Z - Nanoscale Res Lett (2011)

AFM image (1 × 1 μm2) of GeSi nanowires after 0.8 nm Ge deposition on a vicinal Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The black arrow indicates the miscut direction. The inset shows the height profile along the white line in the figure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211410&req=5

Figure 1: AFM image (1 × 1 μm2) of GeSi nanowires after 0.8 nm Ge deposition on a vicinal Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The black arrow indicates the miscut direction. The inset shows the height profile along the white line in the figure.
Mentions: Figure 1 showed the surface morphology after 0.8 nm Ge deposition on a Si (001) substrate with ~8° off toward ⟨110⟩ at 560°C. The compact GeSi nanowires were clearly demonstrated. The nanowires were found to be oriented along the miscut direction of ⟨110⟩, as denoted by a black arrow in the figure. This result was consistent with previous ones [20,21]. The height profile along the white line in the figure was shown in the inset of figure, which clearly exhibited the height and the width of the nanowires. The statistical analyses of the height and the width of the GeSi nanowires were 0.84 nm (± 0.28 nm) and 25.2 nm (± 6.41 nm), respectively. The small ratio of height over width of the nanowires demonstrated that these nanowires were much smaller than the GeSi nanowires of lower Ge composition [21]. This is mainly attributed to the high Ge content in the present nanowires with a large misfit strain. It has been found that the sidewalls of such nanowires were mainly composed of {1 0 5} facets [20,21]. However, in our cases, the ratio of height over width of the present nanowires was considerably smaller than that (~0.07) of the nanowires only composed of {1 0 5} facets. Considering {1 0 5} to be energetically favorable facets [23], we proposed that the sidewalls of the present nanowires were partly composed of {1 0 5} facets and others, which can not be distinguished due to the limitation of the resolution of AFM. This different result was attributed to the growth kinetic limitation at the low growth temperature and the high growth rate. Furthermore, the formation of such small nanowires was more energetically favorable than the layer-by-layer growth during Ge deposition on vicinal substrates after a critical thickness [20]. These self-assembled GeSi nanowires on miscut Si (001) substrates was different from that on very-high-index Si (hkl) substrates, where the GeSi nanowires were along the grooves composed of hill-and-valley structure [16].

Bottom Line: These results proposed that the formation of the nanowire was energetically driven under growth kinetic assistance.Three-dimensionally self-assembled GeSi nanowires were first realized via multilayer Ge growth separated with Si spacers.These GeSi nanowires were readily embedded in Si matrix and compatible with the sophisticated Si technology, which suggested a feasible strategy to fabricate nanowires for fundamental studies and a wide variety of applications.PACS: 81.07.Gf, 81.16.Dn, 68.65.-k, 68.37.Ps.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Handan Str, 220, Shanghai 200433, China. zhenyangz@fudan.edu.cn.

ABSTRACT
: Very small and compactly arranged GeSi nanowires could self-assembled on vicinal Si (001) substrates with ~8° off toward ⟨110⟩ during Ge deposition. The nanowires were all oriented along the miscut direction. The small ration of height over width of the nanowire indicated that the nanowires were bordered partly with {1 0 5} facets. These self-assembled small nanowires were remarkably influenced by the growth conditions and the miscut angle of substrates in comparison with large dome-like islands obtained after sufficient Ge deposition. These results proposed that the formation of the nanowire was energetically driven under growth kinetic assistance. Three-dimensionally self-assembled GeSi nanowires were first realized via multilayer Ge growth separated with Si spacers. These GeSi nanowires were readily embedded in Si matrix and compatible with the sophisticated Si technology, which suggested a feasible strategy to fabricate nanowires for fundamental studies and a wide variety of applications.PACS: 81.07.Gf, 81.16.Dn, 68.65.-k, 68.37.Ps.

No MeSH data available.


Related in: MedlinePlus