Growth of silicon nanowires by chemical vapour deposition on gold implanted silicon substrates

Stelzner, Thomas; Andrä, G.; Wendler, E.; Wesch, W.; Scholz, Roland; Gösele, U.; Christiansen, Silke

doi:10.1088/0957-4484/17/12/012

Cited by 73 publications

(64 citation statements)

References 9 publications

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“…56 The Si NWs with low index surface (100) were the majority. 53 Note: The surface energy, γ, of Si NWs is inversely proportional to the surface atomic densities of the facet. On the basis of this fact, it comes out that γ(100) > γ(110) > γ(111); cf.…”

Section: Resultsmentioning

confidence: 99%

Covalent Attachment of Alkyl Functionality to 50 nm Silicon Nanowires through a Chlorination/Alkylation Process

et al. 2009

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For many applications, the presence of oxide on Si nanowires (Si NWs) is undesirable because of the difficulty in controlling the SiO 2 /Si interface properties. Here, we report on the functionalization of 50 nm (in diameter) Si NWs with alkyl chains using a versatile two step chlorination/alkylation process, while preserving the original length and diameter of the NWs. We show that Si NWs terminated with C 1 -C 10 molecules, through Si-C bonds, connect alkyl molecules to 50-100% of the Si atop sites and provide surface stability that depends on the chain length and molecular coverage. These observation were explained by noting that the longer the alkyl chain the higher the concentration of molecule-free pinholes on the Si NW surfaces and, therefore, the easier the oxidation process. Our results provide evidence that alkyl-Si NWs provide stronger Si-C bonds and higher surface stability in ambient conditions than equivalent two-dimensional (2D) Si surfaces having similar or higher initial coverage. The kinetic mechanism of the alkylation process of Si NW surfaces, the oxidation resistance of the modified structures, and the differences from 2D surfaces are discussed in the article.

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Section: Resultsmentioning

confidence: 99%

Covalent Attachment of Alkyl Functionality to 50 nm Silicon Nanowires through a Chlorination/Alkylation Process

et al. 2009

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“…[18][19][20] The recent emergence of self catalytic 15,[21][22][23][24][25] growth systems for Ge NW formation has allowed high yield growth, often from low cost precursors. 26 Using the correct conditions, spontaneous NW formation with defect free morphologies and tight diameter distributions have been achieved.…”

Section: Introductionmentioning

confidence: 99%

High Density Germanium Nanowire Growth Directly from Copper Foil by Self-Induced Solid Seeding

et al. 2011

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Herein, we describe the growth of highly dense germanium nanowire mats directly on copper foil by a self induced, solid seeded protocol. The existence of Cu 3 Ge tips on each of the nanowires indicates that growth proceeds via a solid catalyzed route, dependent on the in situ formation of the germanide intermediate. The nanowires show a tight diameter distribution and typically <110> growth directions resulting from similarities in the d-spacings between the nanowire and the catalyst seed. The nanowires and substrates were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX) and electron backscatter diffraction (EBSD).

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“…4 These Si NWs were terminated with methyl (CH 3 s), propenyl (CH 3 sCHdCHs), and propynyl (CH 3 sCtCs) functionalities using a chlorination/ alkylation route, 5 as described in section 2 of the Supporting Information. The obtained samples were characterized by high resolution X-ray photo electron spectroscopy (XPS); see Supporting Information, section 3.1.…”

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confidence: 99%

“…9 In this context, it should be mentioned that the 2D Si(111) surfaces have a higher concentration of (111) facets than Si NWs, which (in addition to the (111) facets) contain (100) and (112) too. 4 2D Si(111) surfaces terminated with CH 3 s functionalities exhibited lower oxidation resistance than equivalent Si NWs (cf. Figure 1 above and Figure 4S of the Supporting Information).…”

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confidence: 99%

Stable Scaffolds for Reacting Si Nanowires with Further Organic Functionalities while Preserving Si−C Passivation of Surface Sites

et al. 2008

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Silicon nanowires (Si NWs) represent an attractive class of building blocks for nanoelectronics and sensors. However, for many applications, the presence of oxide on the Si NW surface is undesirable, because a defective oxide layer (e.g., native SiO 2 ) induces uncontrolled interface states in the band gap of the Si.Freshly prepared H-terminated Si NWs have low surface recombination velocities but are not stable in air for more than a few hours, because disordered oxide layers form.1 Recently, we have reported on Si NWs that were chemically modified by CH 3 functionalities through a covalent Si-C bond.2 The resulting CH 3 -Si NWs allowed formation of air-stable Si NW Field Effect Transistors (FETs) having on-off ratios in excess of 10 5 over a relatively small gate voltage swing ((2 V).2 Though CH 3 termination gives full coverage of the Si atop sites, 3 subsequent functionalization is not possible. The ability to attach a controlled functionality to a stable, fully passivated Si NW is highly desirable for a wide range of applications, especially for biosensors and systematic control over the electrical properties of Si NWs.Here, we report on Si NWs modified by covalent CH 3 s CHdCHs scaffolds, via SisC bonds, that give nearly full coverage of the Si atop sites and, at the same time, provide a route for subsequent functionalization. The obtained CH 3 sCHdCHsSi NWs exhibit superior oxidation resistance over Si NWs that are modified with CH 3 s or CH 3 sCtCs functionalities, which give nearly full coverage of the Si atop site too.The Si NWs investigated here were composed of 50 ( 10 nm diameter Si cores coated with 3-4 nm native SiO 2 skins (see Supporting Information, Figure 1S) and contained pronounced low index facets, such as (111), (100), and (112). 4 These Si NWs were terminated with methyl (CH 3 s), propenyl (CH 3 sCHdCHs), and propynyl (CH 3 sCtCs) functionalities using a chlorination/ alkylation route, 5 as described in section 2 of the Supporting Information. The obtained samples were characterized by high resolution X-ray photo electron spectroscopy (XPS); see Supporting Information, section 3.1. The measurements were done three times for each sample, and averages have been taken. Figure 2S of the Supporting Information shows an XPS scan of Si2p and C1s regions of propenyl-terminated Si NWs. The Si2p spectrum shows Si2p 3/2 and Si2p 1/2 in the expected 2:1 area ratio. No oxidized Si between 101.0 and 103.5 eV was observed (see Supporting Information, Figure 2SA). Three peaks were observed in the C1s region (see Supporting Information, Figure 2SB): (i) a peak at 284.0 eV for carbon atoms covalently bonded to silicon (C-Si); 5 (ii) a peak at 285.0 eV for carbons bonded to either hydrogen or another carbon atoms; and (iii) a peak at 286.6 eV for adventitious carbons bonded to oxygen from the wet chemical processing with THF and/or methanol rinse after functionalization. All the C1s and Si2p peaks mentioned were also observed for methyl-and propynyl-terminated Si NWs. The peak area ratio of the C-Si to the ...

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Growth of silicon nanowires by chemical vapour deposition on gold implanted silicon substrates

Cited by 73 publications

References 9 publications

Covalent Attachment of Alkyl Functionality to 50 nm Silicon Nanowires through a Chlorination/Alkylation Process

Covalent Attachment of Alkyl Functionality to 50 nm Silicon Nanowires through a Chlorination/Alkylation Process

High Density Germanium Nanowire Growth Directly from Copper Foil by Self-Induced Solid Seeding

Stable Scaffolds for Reacting Si Nanowires with Further Organic Functionalities while Preserving Si−C Passivation of Surface Sites

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