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| 2. |
- Lee, SangWook, et al.
(författare)
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A three-terminal carbon nanorelay
- 2004
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Ingår i: Nano letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 4:10, s. 2027-2030
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Tidskriftsartikel (refereegranskat)abstract
- Three-terminal nanorelay structures were fabricated with multiwall carbon nanotubes (MWNTs). The nanotube relays were deflected by applying a gate voltage until contact (mechanical and/or electrical) was made with a drain electrode, thus closing the circuit. It was possible to achieve multiple switching cycles, showing that carbon nanotubes are suitable and practical systems for developing nanoelectromechanical devices of this kind.
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| 3. |
- Morjan, Raluca Elena, 1976, et al.
(författare)
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High growth rates and wall decoration of carbon nanotubes grown by plasma-enhanced chemical vapour deposition
- 2004
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 383/4, s. 385-390
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- DC plasma-enhanced chemical vapour deposition (PECVD) was used to grow films of aligned carbon nanotubes on a silicon wafer using Fe as catalyst and a C2H2/H2 gas mixture. The films were of high quality and showed an exceptionally high growth rate compared with other plasma growth techniques. For long growth times, the upper parts of the nanotubes developed additional outer graphite flakes. The onset of the ‘tube decoration’ correlates with a decrease in linear growth rate and can be related to the gradient of plasma parameters in the cathode sheath.
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| 4. |
- Morjan, Raluca Elena, 1976, et al.
(författare)
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Selective growth of individual multiwalled carbon nanotubes
- 2004
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Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 4:6, s. 591-594
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Tidskriftsartikel (refereegranskat)abstract
- Growth of individual, vertically aligned multiwalled carbon nanotubes (VACNT) on patterned Si wafers using dc plasma-enhanced CVD is described. The selective growth of individual VACNT within larger holes etched in Si is demonstrated for the first time.
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| 5. |
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| 6. |
- Yu, H.Y., et al.
(författare)
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Current enhancement with alternating gate voltage in the Coulomb blockade regime of a single wall carbon nanotube
- 2004
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 79, s. 1613-1615
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the current–voltage characteristics of a carbon nanotube in a single electron transistor structure with alternating gate voltage. A continuous current enhancement effect with increasing frequency of the applied gate voltage up to 13 MHz is reported. Assuming that I=nef, more than 1000 electrons are driven to flow across the source–drain channel at VDS=100 mV, 13 MHz of gate voltage (Vp-p=2 V) and T=1.8 K. The continuous current enhancement is explained by the broadening effect of the discrete energy levels of the finite-length carbon nanotube.
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| 7. |
- Boyle, Mark, et al.
(författare)
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Two colour pump-probe study and internal energy dependence of Rydberg state excitation
- 2004
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Ingår i: Physical Review A. - 1050-2947. ; 70
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Tidskriftsartikel (refereegranskat)abstract
- Excitation of Rydberg states in isolated C60 is studied by time-resolved photoelectron spectroscopy in a femtosecond two-color pump-probe experiment. The relaxation time for electron-electron interaction is determined to be approximately 100 fs with the t1g(LUMO + 1) orbital being considered to define the doorway state in a nonadiabatic multielectron excitation process. The internal energy stored in vibrational modes of the C60 at 770 K is found to support the excitation process very efficiently while in "cold" C60 (80 K), no significant Rydberg population is detected.
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| 8. |
- Bulgakov, Alexander, 1956, et al.
(författare)
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Phosphorus cluster production by laser ablation
- 2004
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 79, s. 1369-1372
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Tidskriftsartikel (refereegranskat)abstract
- Neutral and charged phosphorus clusters of a wide size range have been produced by pulsed laser ablation (PLA) in vacuum at 532, 337, and 193 nm ablating wavelengths and investigated by time-of-flight mass spectrometry. The neutral Pn clusters are even-numbered with local abundance maxima at n=10 and 14, while the cationic and anionic clusters are preferentially odd-numbered with P7+, P21+, and P17- being the most abundant ions. The dominance of the magic clusters is more pronounced at 337-nm ablation that is explained by efficient direct ejection of their building blocks under these conditions. Nanocrystalline phosphorus films have been produced by PLA in ambient helium gas.
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| 9. |
- Bulgakova, Nadya, 1956, et al.
(författare)
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Electronic transport and consequences for material removal in ultrafst pulsed laser ablation of materials
- 2004
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Ingår i: Physical Review B. - 1098-0121. ; 69
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Tidskriftsartikel (refereegranskat)abstract
- Fast electronic transport is investigated theoretically based on a drift-diffusion approach for different classes of materials (metals, semiconductors, and dielectrics) under ultrafast, pulsed laser irradiation. The simulations are performed at intensities above the material removal threshold, characteristic for the ablation regime. The laser-induced charging of dielectric surfaces causes a subpicosecond electrostatic rupture of the superficial layers, an effect which, in comparison, is strongly inhibited for metals and semiconductors as a consequence of superior carrier transport properties.
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| 10. |
- Bulgakova, Nadya, 1956, et al.
(författare)
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Model description of surface charging during ultrafast pulsed laser ablationof materials
- 2004
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 79, s. 1153-1155
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Tidskriftsartikel (refereegranskat)abstract
- We present a model describing the dynamical mechanisms responsible for generating fast ion ejection under ultra-short pulsed laser irradiation. The model is based on a simplified drift–diffusion approach describing the evolution of the laser-generated charge carriers, their transport, and the electric field generated as a result of quasi-neutrality breaking in the irradiated target. The importance of different processes in generating the non-thermal material-ejection mechanisms is discussed. A common frame is applied to dielectrics, semiconductors, and metals and different dynamical behaviour is observed. The modelling results are in good agreement with fs pump–probe studies and measurements of the velocity distributions of the emitted ions.
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