| 1. |
- Rehman, Adil, et al.
(författare)
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Low Frequency Noise of Carbon Nanotubes THz detectors
- 2021
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Ingår i: 2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- We report studies of noise properties of carbon nanotube (CNT) networks-based devices used for the terahertz detectors. Low-frequency noise characteristics of CNTs as a function of temperature, UV illumination, and back-gate voltages were examined. Our results demonstrated the existence of at least two important resistance components of nanotubes rather than generally accepted dominant tube-to-tube junction resistance. We showed that noise spectroscopy can be employed to probe the structural quality of nanotube networks. Measurements as a function of back gate voltages revealed the existence of generation-recombination noise, related to deep tarps, which play a significant role in the performances of CNT networks-based terahertz detectors.
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| 2. |
- Rehman, A., et al.
(författare)
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Generation-recombination and 1/f noise in carbon nanotube networks
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118:24
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Tidskriftsartikel (refereegranskat)abstract
- The low-frequency noise is of special interest for carbon nanotubes devices, which are building blocks for a variety of sensors, including radio frequency and terahertz detectors. We studied noise in as-fabricated and aged carbon nanotube networks (CNNs) field-effect transistors. Contrary to the majority of previous publications, as-fabricated devices demonstrated the superposition of generation-recombination (GR) and 1/f noise spectra at a low-frequency range. Although all the devices revealed identical current-voltage characteristics, GR noise was different for different transistors. This effect is explained by the different properties and concentrations of trap levels responsible for the noise. Unexpectedly, exposure of these devices to the atmosphere reduced both the resistance and GR noise due to nanotube's p-doping by adsorbed water molecules from the ambient atmosphere. The presence of the generation recombination noise and its dependences on the environment provides the basis for selective gas sensing based on the noise measurements. Our study reveals the noise properties of CNNs that need to be considered when developing carbon nanotubes-based selective gas sensors.
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| 3. |
- Smulko, J., et al.
(författare)
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Low-frequency noise in Au-decorated graphene-Si Schottky barrier diode at selected ambient gases
- 2023
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 122:21
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Tidskriftsartikel (refereegranskat)abstract
- We report results of the current-voltage characteristics and low-frequency noise in Au nanoparticle (AuNP)-decorated graphene-Si Schottky barrier diodes. Measurements were conducted in ambient air with addition of either of two organic vapors, tetrahydrofuran [(CH2)(4)O; THF] and chloroform (CHCl3), as also during yellow light illumination (592 nm), close to the measured particle plasmon polariton frequency of the Au nanoparticle layer. We observed a shift of the DC characteristics at forward voltages (forward resistance region) when tetrahydrofuran vapor was admitted (in a Au-decorated graphene-Si Schottky diode), and a tiny shift under yellow irradiation when chloroform was added (in not decorated graphene-Si Schottky diode). Significantly larger difference in the low-frequency noise was observed for the two gases during yellow light irradiation, compared with no illumination. The noise intensity was suppressed by AuNPs when compared with noise in graphene-Si Schottky diode without an AuNP layer. We conclude that flicker noise generated in the investigated Au-decorated Schottky diodes can be utilized for gas detection.
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