Abstract
Carbon nanotubes (CNTs) are ideal candidates to be used as field emission sources. Electrodeposition could provide a viable method to deposit CNTs over large areas as part of an industrialized process. It has been shown l,2,3 that CNTs can be co-deposited with nickel onto various substrates, using a suitable CNT dispersant. In the present study, a multiwall carbon nanotube (MWNT): nickel (Ni) composite has been electrodeposited without the use of a dispersant. The field emission properties of the resulting electrodeposits were studied. Unpurified MWNTs grown by CVD were added to a Ni plating bath comprising of IM NiSO4·6H2O, 0.2M NiCl and 0.5M H3BO3. Due to their hydrophobic nature, MWNTs did not disperse naturally, so the plating solution was placed in a sonic bath for 15 minutes before electrodeposition. Electrochemical measurements were conducted using a μAutolab computer controlled potentiostat with a three-electrode configuration and typical cell volume of 10 cm3. A spiral wound platinum wire served as the counter electrode with a Ag:AgCl wire reference electrode. Cu plates were used as cathodes, with an exposed surface area of 2 cm2. After deposition, samples were thoroughly rinsed in deionised water to remove Ni salts. The resulting electrodeposits were imaged using a scanning electron microscope (FIG.1) Importantly, these deposits were observed after the samples were thoroughly rinsed in deionised water, suggesting that there is a strong adhesion between the nickel coated nanotubes and the substrate surface. FIG.1 (a) shows MWNTs (0.013 mg/ml) electrodeposited directly after sonication. Note that a thick Ni coating is not observed (see inset), and that uniform MWNT deposition is observed over a relatively large area. FIG.1(b) shows MWNTs deposited with the same solution after five minutes. A much thicker Ni coating indicates that a relatively higher concentration of Ni to MWNT was present. This was probably due to a rebundling of MWNTs over time, after the sonication process. FIG.1(c) and (d) show MWNTs deposited with a much lower concentration (0.005 mg/ml), and therefore relatively higher concentration of Ni, resulting in thicker Ni coating. Beads of Ni (visible in FIG.1(d)), approximately one micron in diameter completely encased the MWNTs, previously observed by Aria et al.,4 using a poly(acrylic acid) dispersant. Subsequently, the substrates were subjected to field emission characterisation using a 5 mm spherical stainless steel anode. The emission current was recorded as a function of macroscopic electric field at a vacuum of around 10 -6 mbar. The threshold field was taken to be the field at which an emission current of 1 nA was detected and the macroscopic field was calculated by dividing the applied voltage by the electrode gap, which was typically 25 μm. Threshold fields of the order 20 V/μm were observed (FIG.2), after conditioning. It is expected that by altering the deposition conditions, the much lower threshold fields would be observed.
| Original language | English |
|---|---|
| Title of host publication | Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 |
| Pages | 304-305 |
| Number of pages | 2 |
| DOIs | |
| Publication status | Published - Dec 1 2005 |
| Event | Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 - Oxford, United Kingdom Duration: Jul 10 2005 → Jul 14 2005 |
Publication series
| Name | Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 |
|---|---|
| Volume | 2005 |
Other
| Other | Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 |
|---|---|
| Country | United Kingdom |
| City | Oxford |
| Period | 7/10/05 → 7/14/05 |
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All Science Journal Classification (ASJC) codes
- Engineering(all)
Cite this
Field emission from multiwall carbon nanotubes prepared by electrodeposition without the use of a dispersant. / Lyth, S. M.; Oyeleye, F.; Curry, R. J.; Silva, S. R.P.; Davis, J.
Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005. 2005. p. 304-305 1619607 (Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005; Vol. 2005).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Field emission from multiwall carbon nanotubes prepared by electrodeposition without the use of a dispersant
AU - Lyth, S. M.
AU - Oyeleye, F.
AU - Curry, R. J.
AU - Silva, S. R.P.
AU - Davis, J.
PY - 2005/12/1
Y1 - 2005/12/1
N2 - Carbon nanotubes (CNTs) are ideal candidates to be used as field emission sources. Electrodeposition could provide a viable method to deposit CNTs over large areas as part of an industrialized process. It has been shown l,2,3 that CNTs can be co-deposited with nickel onto various substrates, using a suitable CNT dispersant. In the present study, a multiwall carbon nanotube (MWNT): nickel (Ni) composite has been electrodeposited without the use of a dispersant. The field emission properties of the resulting electrodeposits were studied. Unpurified MWNTs grown by CVD were added to a Ni plating bath comprising of IM NiSO4·6H2O, 0.2M NiCl and 0.5M H3BO3. Due to their hydrophobic nature, MWNTs did not disperse naturally, so the plating solution was placed in a sonic bath for 15 minutes before electrodeposition. Electrochemical measurements were conducted using a μAutolab computer controlled potentiostat with a three-electrode configuration and typical cell volume of 10 cm3. A spiral wound platinum wire served as the counter electrode with a Ag:AgCl wire reference electrode. Cu plates were used as cathodes, with an exposed surface area of 2 cm2. After deposition, samples were thoroughly rinsed in deionised water to remove Ni salts. The resulting electrodeposits were imaged using a scanning electron microscope (FIG.1) Importantly, these deposits were observed after the samples were thoroughly rinsed in deionised water, suggesting that there is a strong adhesion between the nickel coated nanotubes and the substrate surface. FIG.1 (a) shows MWNTs (0.013 mg/ml) electrodeposited directly after sonication. Note that a thick Ni coating is not observed (see inset), and that uniform MWNT deposition is observed over a relatively large area. FIG.1(b) shows MWNTs deposited with the same solution after five minutes. A much thicker Ni coating indicates that a relatively higher concentration of Ni to MWNT was present. This was probably due to a rebundling of MWNTs over time, after the sonication process. FIG.1(c) and (d) show MWNTs deposited with a much lower concentration (0.005 mg/ml), and therefore relatively higher concentration of Ni, resulting in thicker Ni coating. Beads of Ni (visible in FIG.1(d)), approximately one micron in diameter completely encased the MWNTs, previously observed by Aria et al.,4 using a poly(acrylic acid) dispersant. Subsequently, the substrates were subjected to field emission characterisation using a 5 mm spherical stainless steel anode. The emission current was recorded as a function of macroscopic electric field at a vacuum of around 10 -6 mbar. The threshold field was taken to be the field at which an emission current of 1 nA was detected and the macroscopic field was calculated by dividing the applied voltage by the electrode gap, which was typically 25 μm. Threshold fields of the order 20 V/μm were observed (FIG.2), after conditioning. It is expected that by altering the deposition conditions, the much lower threshold fields would be observed.
AB - Carbon nanotubes (CNTs) are ideal candidates to be used as field emission sources. Electrodeposition could provide a viable method to deposit CNTs over large areas as part of an industrialized process. It has been shown l,2,3 that CNTs can be co-deposited with nickel onto various substrates, using a suitable CNT dispersant. In the present study, a multiwall carbon nanotube (MWNT): nickel (Ni) composite has been electrodeposited without the use of a dispersant. The field emission properties of the resulting electrodeposits were studied. Unpurified MWNTs grown by CVD were added to a Ni plating bath comprising of IM NiSO4·6H2O, 0.2M NiCl and 0.5M H3BO3. Due to their hydrophobic nature, MWNTs did not disperse naturally, so the plating solution was placed in a sonic bath for 15 minutes before electrodeposition. Electrochemical measurements were conducted using a μAutolab computer controlled potentiostat with a three-electrode configuration and typical cell volume of 10 cm3. A spiral wound platinum wire served as the counter electrode with a Ag:AgCl wire reference electrode. Cu plates were used as cathodes, with an exposed surface area of 2 cm2. After deposition, samples were thoroughly rinsed in deionised water to remove Ni salts. The resulting electrodeposits were imaged using a scanning electron microscope (FIG.1) Importantly, these deposits were observed after the samples were thoroughly rinsed in deionised water, suggesting that there is a strong adhesion between the nickel coated nanotubes and the substrate surface. FIG.1 (a) shows MWNTs (0.013 mg/ml) electrodeposited directly after sonication. Note that a thick Ni coating is not observed (see inset), and that uniform MWNT deposition is observed over a relatively large area. FIG.1(b) shows MWNTs deposited with the same solution after five minutes. A much thicker Ni coating indicates that a relatively higher concentration of Ni to MWNT was present. This was probably due to a rebundling of MWNTs over time, after the sonication process. FIG.1(c) and (d) show MWNTs deposited with a much lower concentration (0.005 mg/ml), and therefore relatively higher concentration of Ni, resulting in thicker Ni coating. Beads of Ni (visible in FIG.1(d)), approximately one micron in diameter completely encased the MWNTs, previously observed by Aria et al.,4 using a poly(acrylic acid) dispersant. Subsequently, the substrates were subjected to field emission characterisation using a 5 mm spherical stainless steel anode. The emission current was recorded as a function of macroscopic electric field at a vacuum of around 10 -6 mbar. The threshold field was taken to be the field at which an emission current of 1 nA was detected and the macroscopic field was calculated by dividing the applied voltage by the electrode gap, which was typically 25 μm. Threshold fields of the order 20 V/μm were observed (FIG.2), after conditioning. It is expected that by altering the deposition conditions, the much lower threshold fields would be observed.
UR - http://www.scopus.com/inward/record.url?scp=33947227440&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33947227440&partnerID=8YFLogxK
U2 - 10.1109/IVNC.2005.1619607
DO - 10.1109/IVNC.2005.1619607
M3 - Conference contribution
AN - SCOPUS:33947227440
SN - 0780383974
SN - 9780780383975
T3 - Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005
SP - 304
EP - 305
BT - Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005
ER -