Tobias Hertel

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Carbon nanotubes are novel materials with unique electrical and mechanical properties. Here we present results on their atomic structure and mechanical properties in the adsorbed state, on ways to manipulate individual nanotubes, on their electrical properties and, finally, on the fabrication and characteristics of nanotube-based electron devices.(More)
The dynamics of excitons in individual semiconducting single-walled carbon nanotubes was studied using time-resolved photoluminescence (PL) spectroscopy. The PL decay from tubes of the same (n,m) type was found to be monoexponential, however, with lifetimes varying between less than 20 and 200 ps from tube to tube. Competition of nonradiative decay of(More)
Time-domain spectroscopic studies provide a unique perspective on the materials properties and the microscopic processes underlying them in carbon nano-tubes. Ultrafast spectroscopy is used to study the dynamics and kinetics of scattering and relaxation processes from the femtosecond (1 fs ≡ 10 −15 s) to the picosecond timescale. This provides crucial(More)
Theory predicts peculiar features for excited-state dynamics in one dimension (1D) that are difficult to be observed experimentally. Single-walled carbon nanotubes (SWNTs) are an excellent approximation to 1D quantum confinement, due to their very high aspect ratio and low density of defects. Here we use ultrafast optical spectroscopy to probe(More)
We present a comparative study of the ultrafast photoconductivity in two different forms of one-dimensional (1D) quantum-confined graphene nanostructures: structurally well-defined semiconducting graphene nanoribbons (GNRs) fabricated by a "bottom-up" chemical synthesis approach and semiconducting carbon nanotubes (CNTs) with a similar bandgap energy.(More)
Photonic signal processing requires efficient on-chip light sources with higher modulation bandwidths. Today's conventional fastest semiconductor diode lasers exhibit modulation speeds only on the order of a few tens of GHz due to gain compression effects and parasitic electrical capacitances. Here we theoretically show an electrically-driven carbon(More)
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