Field Emission from Carbon Nanotubes

One feature of carbon nanotubes is of special interest for a variety of applications the field emission. This is the ability to emit electrons upon the application of an electric field. Field emission is no phenomenon exclusive to carbon nanotubes. It has been known for long that electrons can be extracted from the surface of conductive materials. Still it takes in parts extremely high field intensities of up to several kilovolts per micrometer to enable a turmeling through the energy barrier constituted by the surface. Normally such values are not practicable. Hence other approaches are required to facihtate the extraction of electrons. It is a known effect that an electric field is locally intensified at the pointed ends of a sample because the flux lines are more concentrated at highly curved sites. A suitable material must further exhibit a low work function, which means that httle energy is required for the removal of an electron from the sohd to the outside. 

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Bonard J.M., Stockli T., Nilsson L.O., Kind H. (2001) Field emission from carbon nanotubes the first five years. Solid-State Electr. 45 893-914. 

Maiti A., Andzelm J., Tanpipat N., and von Allmen P. (2001) Effect of adsorbates on field emission from carbon nanotubes. Phys. Rev. Lett. 87 15. 

Saito. Y. Hamaguchi, K. Hata, K. Tohji. K, Kasuya, A. Nishina. Y. Uchida. K, Tasaka, Y. Ikazaki. F. Yumura. M. Field emission from carbon nanotubes Purified single-walled and multiwalled tubes. Ultramicroscopy 199 8 73. 1. 

Field emission from carbon nanotubes may be more complex than implied by the analysis above since, in contrast to metal tips, the Fermi wavelengths are comparable to the tip size and consequently electronic states exist, which extend over the entire tip [152,168]. Emission is therefore not from individual atoms but from these tip states such that the emission is coherent. The field emission patterns from individual MWNTs in fact carry the signature of coherent emission from the tip states [168] (see Fig. 36). SWNTs have been imaged as well and the patterns correspond with calculated nanotube charge densities [152]. 

Itoh E, Suzuki 1, Miyairi K (2005) Field emission from carbon-nanotube-dispersed conducting polymer thin film and its application to photovoltaic devices. Jpn J Appl Phys 44 636... 

Figure 3.55 Field emission from carbon nanotubes (a) scheme of an emitter array consisting of carbon nanotubes, (b) emission curve and possible geometries...

Bonard JM, Salvetat JP. et al.. Field emission from carbon nanotubes Perspectives for applications and clues to the emission mechanism. Applied Physics A—Materials Science and Processing, 1999. 69(3) 245-254. 

Zhi CY, Bai XD, Wang EG, Enhanced field emission from carbon nanotubes by hydrogen plasma treatment. Applies P/tysics Letters, 2002. 81(9) 1690-1692. 

Naieni AK, Yaghoobi P, Nojeh A, First-principles study of field-emission from carbon nanotubes in the presence of methane. Journal of Vacuum Science and Technology B, 2012. 30(2) 021803. 

Wong, W., Au, F., BeUo, L., Lee, C., Lee, S. - Field emission from carbon nanotubes grown on plasma treated nickel/silicon substrate . Sixth Applied Diamonds Conference/Second Frontier Carbon Technology, Auburn University, July 2001, NASA/CP-2001-210948... 

Bonard J M, Salvetat J P, Stockli T, Forro L and Chatelain A, Field emission from carbon nanotubes perspectives for applications and clue to the emission mechanism , Appl Phys A, 1999 69 245-254. 

Gupta, S., Wang, Y.Y, GarguUo, J.M., and Nemanich, R.J. (2005). Imaging temperature dependent field emission from carbon nanotube films Single- versus multi-walled. Appl Phys Lett 86 063109/1-063109/3. 

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