A Carbon Nanofilament-Bead Necklace

Li, Song; Holleitner, Alexander W.; Qian, Huihong; Hartschuh, Achim; Döblinger, Markus; Weig, Eva M.; Kotthaus, J. P.

doi:10.1021/jp8018588

Cited by 11 publications

(6 citation statements)

References 36 publications

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“…The diameter of the CNTs is in the range of a few up to 6 nm. Single-walled CNTs typically have a diameter of about 1 -2 nm [19], while a height of 6 nm suggests that bundles of CNTs build the back-bone of the PSI-CNT hybrids [42].…”

Section: Characterizationmentioning

confidence: 99%

The optoelectronic properties of a photosystem I–carbon nanotube hybrid system

et al. 2009

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Abstract. The photoconductance properties of photosystem I (PSI) covalently bound to carbon nanotubes (CNTs) are measured. We demonstrate that the PSI forms active electronic junctions with the CNTs enabling control of the CNTs photoconductance by the PSI. In order to electrically contact the photoactive proteins, a cysteine mutant is generated at one end of the PSI by genetic engineering. The CNTs are covalently bound to this reactive group using carbodiimide chemistry. We detect an enhanced photoconductance signal of the hybrid material at photon wavelengths resonant to the absorption maxima of the PSI compared to nonresonant wavelengths. The measurements prove that it is feasible to integrate photosynthetic proteins into optoelectronic circuits at the nanoscale.

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Section: Characterizationmentioning

confidence: 99%

The optoelectronic properties of a photosystem I–carbon nanotube hybrid system

et al. 2009

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“…[1][2][3][4][5][6] The functionalization of CNTs by chemical modifications holds interesting prospects in various fields such as the fabrication of hybrid bioorganic nanosystems. 7,8 In particular, it has been demonstrated how to bind CNTs to single molecules, 9 photosynthetic proteins, 10 graphite beads, 11 and nanocrystals. [12][13][14][15][16][17] The adjustable optical properties of colloidal semiconductor nanocrystals make them very suitable for optoelectronic devices such as solar cells.…”

Section: Introductionmentioning

confidence: 99%

Optoelectronic sensitization of carbon nanotubes by CdTe nanocrystals

et al. 2009

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We investigate the photoconductance of single-walled carbon nanotube-nanocrystal hybrids. The nanocrystals are bound to the nanotubes via molecular recognition. We find that the photoconductance of the hybrids can be adjusted by the absorption characteristics of the nanocrystals. In addition, the photoconductance of the hybrids surprisingly exhibits a slow time constant of about 1 ms after excitation of the nanocrystals. The data are consistent with a bolometrically induced current increase in the nanotubes caused by photon absorption in the nanocrystals.

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“…Therefore, the gap expansion around the open side almost corresponds to the piezo expansion. The CNTs are grown via electric-field assisted chemical vapor deposition, [31] such that they are mounted on two Au pads. The pads define the source and drain electrodes for the photocurrent measurements, and they are patterned on an insulating SiO 2 layer with a thickness of 100 nm.…”

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confidence: 99%

Photocurrent properties of freely suspended carbon nanotubes under uniaxial strain

Kaniber

Kotthaus

et al. 2009

Applied Physics Letters

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The photocurrent properties of freely suspended single-walled carbon nanotubes (CNTs) are investigated as a function of uniaxial strain. We observe that at low strain, the photocurrent signal of the CNTs increases for increasing strain, while for large strain, the signal decreases, respectively. We interpret the non-monotonous behavior by a superposition of the influence of the uniaxial strain on the resistivity of the CNTs and the effects caused by Schottky contacts between the CNTs and the metal contacts. Corresponding author: holleitner@wsi.tum.de PACS 73.22.-f, 78.67.Ch, 85.60.-q 2 Carbon nanotubes (CNTs) have attracted considerable attention because of their compelling optoelectronic [1]-[8] and electro-mechanical properties. [9]-[29] For instance, laser-induced excitonic transitions can give rise to a photoconductance of CNTs. [3],[4] A photoconductance can also be bolometrically induced in CNTs, [6],[8] and surface states due to adsorbates can alter the photoconductance of CNTs by laser-excited photodesorption of the molecules. [2] Furthermore, electric fields at the Schottky contacts between CNTs and metal contacts can separate optically excited electron-hole pairs, causing a photocurrent across electrically contacted CNTs. [5]-[7]At the same time, the electro-mechanical properties of CNTs have been studied both by locally manipulating CNTs with the tip of an atomic force microscope (AFM), [12]-[14] and by applying uniaxial [15]-[18] and torsional [19], [20] strain to the CNTs. Theorists have modeled the electronic behavior of the mechanically deformed CNTs by an enhanced electronic scattering at defects, [13],[21],[22] a structural induced alteration of the CNTs' band gap, [15]-[19],[21],[23]-[25], [29] and by a mechanical induced transition from sp 2 to sp 3 hybridization of the carbon bonds. [11],[28] Here, we report on the photocurrent properties of freely suspended CNTs as a function of statically applied uniaxial strain. To this end, we experimentally verify that the photocurrent is generated at Schottky contacts between the freely suspended CNTs and their bracing source and drain electrodes. Then, the strain is induced by applying a voltage to a piezoelectric stack, such that the distance of the source and drain electrodes is increased. We observe a rise of the photocurrent signal of up to ~150 % for uniaxial strain values in the range of 0.3 to 1.2 % and a decrease of the photocurrent signal for

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A Carbon Nanofilament-Bead Necklace

Cited by 11 publications

References 36 publications

The optoelectronic properties of a photosystem I–carbon nanotube hybrid system

The optoelectronic properties of a photosystem I–carbon nanotube hybrid system

Optoelectronic sensitization of carbon nanotubes by CdTe nanocrystals

Photocurrent properties of freely suspended carbon nanotubes under uniaxial strain

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