Double-walled carbon nanotubes in small bundles produced by catalytic vapour deposition: monodispersity in helicity and structural organization

Transcription

1 Double-walled carbon nanotubes in small bundles produced by catalytic vapour deposition: monodispersity in helicity and structural organization P. Launois 1,*, J.-F. Colomer 2, L. Henrard 2, G. Van Tendeloo 3, A. A. Lucas 2 and Ph. Lambin 2 1 Laboratoire de Physique des Solides (UMR CNRS 8502), Orsay, France * launois@lps.u-psud.fr 2 Laboratoire de Physique du Solide, Namur, Belgium 3 EMAT, Antwerp, Belgium GdR-E, October 2004

2 Introduction Why studying double-wall nanotubes The synthesis Experimental results Transmission Electron Microscopy Electron Diffraction Summary Discussion Energetic calculations Electronic properties Growth mechanism

3 WHY STUDYING DOUBLE-WALL NANOTUBES (DWNTs)? The simplest Multi-Wall Nanotubes (MWNT) Study of the effect of the interlayer interactions on the physical properties Electronic properties : S. Roche, F. Triozon, A. Rubio and D. Mayou, Phys. Rev. B 64, (2001) M. Kociak, K. Suenaga, K. Hirahara, Y. Saito, T. Nakahira and S. Iijima, Phys. Rev. Lett. 89, (2002) Mechanical properties : R. Saito, R. Matsuo, T. Kimura, G. Dresselhaus and M.S. Dresselhaus, Chem. Phys. Lett. 348, 187 (2001) THE SYNTHESIS Decomposition of methane on Co/MgO catalyst, C Further purification by a hydrochloric acid treatment J.-F. Colomer, C. Stephan, S. Lefrant, G. Van Tendeloo, I. Willems, Z. Kónya, A. Fonseca, Ch. Laurent and J.B. Nagy, Chem. Phys. Lett. 317, 83 (2000) E. Flahaut, R. Bacsa, A. Peigney and C. Laurent, Chem. Comm. 12, 1442 (2003)

4 Transmission Electron Microscopy Different fringe spacings along the axis : different crystallographic orientations of the bundle Twist around its axis At least 2 different spacings Single wall nanotubes (SWNT) DWNTs? (a) TEM image of a bundle of DWNTs (b) and (c) : enlarged images of two parts of the bundle Twisted bundle of DWNTs? J.F. Colomer, L. Henrard, P. Launois, G. Van Tendeloo, A.A. Lucas and Ph. Lambin, Chem. Comm., in press

5 Electron Diffraction 1 e - beam 2 3 J.F. Colomer, L. Henrard, P. Launois, G. Van Tandeloo, A.A. Lucas and Ph. Lambin 1: Phys. Rev. B 70, (2004) 2-3: Chem. Comm., in press

6 A. Relative locations of the non-equatorial scattering planes 1 NT Direct space (n,m) Radius R Period T Chiral angle θ Reciprocal space (16,6) nanotube k z d d 2 2θ 3 The sum : over atoms within one unit cell (0 z j <T) Spherical Bessel functions Amelinckx, Lucas & Lambin, Rep. Prog. Phys. 62, 1471 (1999) Scattering : in planes k z Plane locations helicity Gao et al., Appl. Phys. Lett. 82, 2703 (2003) d 1 θ = d atan( 2 2d = atan( d 3d 2 3 3d 1 3 ) d 3 )

7 1 Two chiral angles : θ 1 =0 θ 2 =15.3 Tilt angle of the bundle axis away from the normal to the electron beam~15

8 B. Analysis of the equatorial line l=0 Peak 1, Q=0.67Å -1 : (11) or (20) Bragg peak => lattice parameter a=18.7å or a=21.6å? a=2r+ 3.2Å a=2r out + 3.2Å

9 (R in R out =7.7Å) (R in R out =9.2Å) R=7.7Å R=9.2Å Each bundle is made of 13 tubes. The computed profiles are average spectra over all the 2D crystal orientations (bundle twist).

10 (R in R out =7.7Å) θ 1 =0 θ 2 =15.3 (8,3)@(18,0)? (8,3)@(19,0)? (11,0)@(16,6)? (12,0)@(16,6)? (8,3)@(16,6) & (11,0)@(19,0)?.

11 C. Analysis of the non-equatorial lines Walls relative orientations and positions within a commensurate DWNT DWNTs relative orientations and positions within a bundle

12 The effect of disorder in non equatorial planes Bundle of 13 nanotubes Order Disorder Plane k z =1.47Å -1 =2π/T (11,0) 1

13 Bundle of DWNTs translational disorder between the tubes along the bundle axis

14 2 3 (8,6)@(14,10)

15 SUMMARY (n,m) R θ R 1 (11,0) 4.31Å 7.72Å Å 2 (9,7) 5.44Å 8.86Å Å 3 (8,6) 4.77Å 8.18Å Å - Within a bundle : one sort of DWNT - Organization: translational disorder along the bundle axis - No rule for the helicities of DWNTs in different bundles - R=3.4Å

16 Energy calculations The stability of a DWNT is found not to depend on chirality, but rather on the diameter difference between inner and outer layer R. Saito, R. Matsuo, T. Kimura, G. Dresselhaus and M.S. Dresselhaus, Chem. Phys. Lett. 348, 187 (2001) (9,0)@(18,0) Sliding (8,-2)@(14,5) Discrete (ratchet) motion (8,2)@(17,2) Nano-bolt-nut pair

17 Inner and outer walls interactions Electronic properties S. Roche, F. Triozon, A. Rubio and D. Mayou, Phys. Rev. B 64, (2001) Interactions between DWNTs

18 Growth mechanism - Our finding of identical DWNTs within a bundle Collective growth mechanism from the metal catalyst particle - Differences between bundles Strong dependence on growth conditions (T ) J. Gavillet, J. Thibault, O. Stéphan, H. Amara, A. Loiseau, Ch. Bichara, J.-P. Gaspard and F. Ducastelle, J. Nanosci. Nanotechnology 4, 346 (2004)

19 In brief Detailed analysis of electron diffraction patterns DWNTs with the same chiral angles within a bundle No translational order along the bundle axis Structural features : important / mechanical or electrical properties Collective growth mechanism from the metal catalyst particle