Elsevier

Surface Science

Volume 462, Issues 1–3, 10 August 2000, Pages 195-202
Surface Science

Controlled deposition of carbon nanotubes on a patterned substrate

https://doi.org/10.1016/S0039-6028(00)00609-9Get rights and content

Abstract

We describe a new technique for the preparation of reactive templates of 1,2-aminopropyltriethoxysilane on silica surfaces, based on the chemical vapour deposition of silane molecules through a PMMA mask patterned by conventional electron-beam lithography. The template thickness and width are controlled down to the monolayer and 50 nm ranges respectively. These templates are successfully used for the selective deposition of sodium dodecylsulphate-covered single walled nanotubes at controlled locations on the surface. We demonstrate that this technique allows one to contact nanotubes with metallic electrodes deposited on top of the tubes and opens the way towards the formation of controlled crossings of nanotubes.

Introduction

Carbon nanotubes (NTs), discovered in 1991 [1], have open a promising way in nanotechnology [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. For electronic applications, NTs provide insulating, semiconducting or truly conducting nanoscale wires [3], [4], [5], [6], [7], [8], and components such as a junction [9], [10], [11] and a field-effect transistor [12], [13], [14], [15] have even been demonstrated. For nanomechanics, NTs provide fibres with unprecedented mechanical properties that can be used to fabricate nanotools [16], [17].

However, the fabrication of all kinds of NT-based devices is severely hindered by the lack of a simple and reliable process to deposit NTs in a controlled way. Up to now, all the demonstrated NT electrical devices have been nanofabricated either by randomly depositing NTs on a multi-electrode array or by patterning contacts onto randomly deposited NTs, after their observation [3], [4], [5], [6], [7], [9], [10], [11], [12], [13], [14]. Although alternative methods such as direct NT growth on catalytic templates [18], [19] or between patterned metallic pads [15] have been demonstrated, the lack of a generic solution for the controlled deposition of NTs at given locations of a surface is a major bottleneck. Such a process was recently proposed by Liu et al. [20], relying on a local chemical functionalization of the surface of the substrate. In the present work, we demonstrate another method for achieving this control. This method, described in Fig. 1, is based on the electrostatic anchoring of surfactant covered NTs on amino-silane functionalized surfaces [21]: first, a reactive amino-silane template is prepared using chemical vapour deposition of silane molecules through a PMMA mask patterned by conventional electron-beam lithography. Surfactant covered NTs are then selectively deposited on the template. Finally, the PMMA mask is lifted-off, leaving the tubes on the template. In the following, we describe the method in detail, and we discuss in particular the deposition yield and the alignment quality.

Section snippets

Experimental

The SWNT raw material, produced by the arc discharge method, was purchased as AP grade from CarboLex (Lexington, USA). Surfactant stabilized tube dispersions were prepared by sonication of raw material in an aqueous 1 wt% sodium dodecylsulphate (SDS) solution. After some macroscopic particles had settled (over 10 min), the dark dispersions were loaded into the chromatographic column for purification as described in Ref. [22].

Oxidized silicon substrates (oxide thickness 300 nm) were cleaned as

Results and discussion

As a first step, we investigated the fabrication of a patterned self-assembled monolayer (SAM) of silane based molecules. Several techniques have been described in the literature for the patterning of a SAM of trichloro- or trialkoxy-silane on silica. Most use direct writing in the SAM with either photolithography, ion-beam, e-beam, atomic-beam or scanning probe microscopy lithography [23], [24], [25], [26], [27], [28]. Some use a SAM as resist to etch the underlying substrate or insert another

Conclusion

In this work, we designed a new simple and efficient technique to prepare patterned aminosilane monolayers forming a template suitable for the deposition of SDS-covered NTs at predefined locations. In the course of this work, we showed how gas-phase silane deposition could be controlled down to the monolayer level and a lateral extension of 50 nm, and we demonstrated a simple way for directly measuring the thickness of the silane layer. Using such silanized patterns, we deposited isolated NTs

Acknowledgements

The authors are grateful to S. Palacin and V. Huc for useful discussions and to O. Araspin and P. Orfila for their help with the lithography. This work was supported in part by the EU NANOMOL IST-1999-12603 project2.

References (36)

  • J. Liu et al.

    Chem. Phys. Lett.

    (1999)
  • S. Iijima

    Nature

    (1991)
  • W.A. de Heer et al.

    Adv. Mater.

    (1997)
  • J.W. Mintmire et al.

    Phys. Rev. Lett.

    (1992)
  • N. Hamada et al.

    Phys. Rev. Lett.

    (1992)
  • M.S. Dresselhaus et al.

    Science of Fullerenes and Carbon Nanotubes

    (1996)
  • S.J. Tans et al.

    Nature

    (1997)
  • M. Bockrath et al.

    Science

    (1997)
  • P.G. Collins et al.

    Science

    (1997)
  • R.D. Antonov et al.

    Phys. Rev. Lett.

    (1999)
  • Z. Yao et al.

    Nature

    (1999)
  • M.S. Fuhrer et al.

    Science

    (2000)
  • S.J. Tans et al.

    Nature

    (1998)
  • R. Martel et al.

    Appl. Phys. Lett.

    (1998)
  • L. Roschier et al.

    Appl. Phys. Lett.

    (1999)
  • H.T. Soh et al.

    Appl. Phys. Lett.

    (1999)
  • H. Dai et al.

    Nature

    (1996)
  • P. Kim et al.

    Science

    (1999)
  • Cited by (123)

    • Detection of a secreted protein biomarker for citrus Huanglongbing using a single-walled carbon nanotubes-based chemiresistive biosensor

      2020, Biosensors and Bioelectronics
      Citation Excerpt :

      Five μL of SWNT solution was drop-casted onto the patterned APTES region and the droplet was allowed to dry in air overnight. The anionic surfactant molecules, which are physisorbed to the SWNTs, are electrostatically attracted to the amino groups of the APTES covered surface, which consequently anchors the SWNTs onto the APTES-functionalized SiO2 surface (Choi et al., 2000; Liu et al., 1999; Sarkar and Daniels-Race, 2013). Washing the device with distilled water removes excess unbound and weakly bound SWNTs and excess surfactant molecules from the sensor surface.

    • Directed Assembly of Carbon Nanotubes

      2017, Comprehensive Supramolecular Chemistry II
    View all citing articles on Scopus
    1

    Present address: MCP-NM, IMEC vzw, Kapeldreef 75, B-3001 Leuven, Belgium.

    View full text