| 1. |
- Li, Jiantong, et al.
(författare)
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Contact-electrode insensitive rectifiers based on carbon nanotube network transistors
- 2008
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 29:5, s. 500-502
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents rectifiers based on the diode connection of carbon nanotube network (CNN) transistors. Despite a low density of carbon nanotubes in the CNNs, the devices can achieve excellent performance with a forward/reverse current ratio reaching 10(5). By casting nanotube suspension on oxidized Si substrates with predefined electrodes, CNN-based field-effect transistors are readily prepared. By short-circuiting the source and gate terminals, CNN-based rectifiers are realized with the rectification characteristics independent of whether Pd or Al is employed as the contact electrodes. This independence is especially attractive for applications of CNN-based transistors/rectifiers in flexible electronics with various printing techniques.
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| 2. |
- Li, Jiantong, et al.
(författare)
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Distinguishing self-gated rectification action from ordinary diode rectification in back-gated carbon nanotube devices
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 92:133111
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Tidskriftsartikel (refereegranskat)abstract
- Self-gating leading to rectification action is frequently observed in two-terminal devices built from individual or networked single-walled carbon nanotubes (SWCNTs) on oxidized Si substrates. The current-voltage (I-V) curves of these SWCNT devices remain unaltered when switching the measurement probes. For ordinary diodes, the I-V curves are symmetric about the origin of the coordinates when exchanging the probes. Numerical simulations suggest that the self-gated rectification action should result from the floating semiconducting substrate which acts as a back gate. Self-gating effect is clearly not unique for SWCNT devices. As expected, it is absent for devices fabricated on insulating substrates.
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| 3. |
- Li, Jiantong, et al.
(författare)
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Finite-size scaling in stick percolation
- 2009
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1063-651X .- 1095-3787. ; 80:4
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Tidskriftsartikel (refereegranskat)abstract
- This work presents the generalization of the concept of universal finite-size scaling functions to continuum percolation. A high-efficiency algorithm for Monte Carlo simulations is developed to investigate, with extensive realizations, the finite-size scaling behavior of stick percolation in large-size systems. The percolation threshold of high precision is determined for isotropic widthless stick systems as N(c)l(2)=5.637 26 +/- 0.000 02, with N-c as the critical density and l as the stick length. Simulation results indicate that by introducing a nonuniversal metric factor A=0.106 910 +/- 0.000 009, the spanning probability of stick percolation on square systems with free boundary conditions falls on the same universal scaling function as that for lattice percolation.
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| 4. |
- Li, Jiantong, et al.
(författare)
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Improved electrical performance of carbon nanotube thin film transistors by utilizing composite networks
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 92:133103
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a simple scheme of using composite carbon nanotube networks (c-CNNs) to significantly improve the electrical performance of long-channel thin film transistors based on single-walled carbon nanotubes (SWCNTs). Such c-CNNs comprise two sets of SWCNTs. A primary set consists of dense arrays of perfectly aligned long SWCNTs along the transistor channel direction. A secondary set is composed of short SWCNTs either randomly orientated or perpendicularly aligned with respect to the channel. While retaining a high on/off current ratio, the drive current in such c-CNNs is much higher than that in currently studied systems with single CNNs or SWCNT arrays.
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| 5. |
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| 6. |
- Li, Jiantong, et al.
(författare)
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Percolation in random networks of heterogeneous nanotubes
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:253127
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Tidskriftsartikel (refereegranskat)abstract
- The electrical performance of random carbon nanotube network transistors is found by Monte Carlo simulation to strongly depend on the nature of the conduction path percolating the network. When the network is percolated only by semiconducting nanotube pathways (OSPs), the transistors can directly achieve both high on current and large on/off current ratio. Based on percolation theory, the present work predicts that there exist specific nanotube coverage domains within which OSP has the highest probability and becomes predominant. Simulation results show that the coverage domains depend on the network dimension, nanotube length, and the fraction of metallic nanotubes.
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| 7. |
- Li, Jiantong, et al.
(författare)
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Understanding doping effects in biosensing using carbon nanotube network field-effect transistors
- 2009
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 79:155434
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Tidskriftsartikel (refereegranskat)abstract
- Systematic theoretical studies based on a comprehensive heterogeneous stick percolation model are performed to gain insights into the essence of doping effects in electrical sensing of biomolecules, such as proteins and DNA fragments, using carbon nanotube network field-effect transistors (CNNFETs). The present work demonstrates that the electrical response to doping of CNNFETs is primarily caused by conductance change at the electrode-nanotube contacts, in contrast to that in the channel as assumed previously. However, the presence of intertube junctions in the channel could reduce the sensitivity of CNNFET-based biosensors and is partially responsible for the experimentally observed channel-length dependent sensitivity.
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| 8. |
- Zhang, Zhi-Bin, et al.
(författare)
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Photo-Activated Interaction Between P3HT and Single-Walled Carbon Nanotubes Studied by Means of Field-Effect Response
- 2009
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 30:12, s. 1302-1304
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Tidskriftsartikel (refereegranskat)abstract
- It is shown in this letter that the field-effect electrical response of transistors with their channel made of networks of single-walled carbon nanotubes (SWNTs) embedded in a poly(3-hexylthiophene) (P3HT) matrix can be significantly altered by light illumination. The experimental results indicate a photo-activated electron transfer from P3HT selectively to the semiconducting SWNTs. This finding points to a potential optoelectronic application of such a field-effect device as a photo-triggered electronic switch.
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| 9. |
- Zhang, Zhibin, et al.
(författare)
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Characterization of acid-treated carbon nanotube thin films by means of Raman spectroscopy and field-effect response
- 2009
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 476:4-6, s. 258-261
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Tidskriftsartikel (refereegranskat)abstract
- By combining Raman spectroscopy with transistor transfer characteristics, acid treatment of single-walled carbon nanotubes (SWCNTs) in a mixture of concentrated HNO3/H2SO4 has been characterized. The acid treatment results in a sharp decrease in the Raman resonant signals of the metallic SWCNTs but no observable change in those of the semiconducting SWCNTs. However, the acid treatment causes disappearing gate modulation of the thin-film transistors made of the SWCNTs, contrary to what would be expected referring to the Raman results. These experimental results suggest that the energy band of the semiconducting SWCNTs is significantly affected by absorbates induced by the acid treatment.
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| 10. |
- Zhang, Zhibin, et al.
(författare)
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Photo-Activated Interaction Between P3HT and Single-Walled Carbon Nanotubes Studied by Means of Field-Effect Response
- 2009
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 30:12, s. 1302-1304
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Tidskriftsartikel (refereegranskat)abstract
- It is shown in this letter that the field-effect electrical response of transistors with their channel made of networks of single-walled carbon nanotubes (SWNTs) embedded in a poly(3-hexylthiophene) (P3HT) matrix can be significantly altered by light illumination. The experimental results indicate a photo-activated electron transfer from P3HT selectively to the semiconducting SWNTs. This finding points to a potential optoelectronic application of such a field-effect device as a photo-triggered electronic switch.
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