Field Emission Properties of Carbon Nanotube Arrays with Defects and Impurities

Roy Mahapatra, D., Sinha, N., Melnik, R.V.N., and Yeow, J.T.W.

Proc. 11th Annual NSTI Nanotech Conference, Boston, Massachusetts, USA, June 1-5, 2008, NSTI-Nanotech 2008, ISBN 978-1-4200-8505-1, Vol. 3, pp. 729 – 732, 2008

Abstract:

It has been found experimentally that the results related to the collective field emission performance of carbonnanotube (CNT) arrays show variability. The emission performance depends on the electronic structure of CNTs (especially their tips). Due to limitations in the synthesis process, production of highly pure and defect free CNTs is very difficult. The presence of defects and impurities affects the electronic structure of CNTs. Therefore, it is essential to analyze the effect ofdefects on the electronic structure, and hence, the field emission current. In this paper, we develop a modeling approach for evaluating the effect of defects and impurities on the overall field emission performance of a CNT array. We employ a concept of effective stiffness degradation for segments of CNTs, which is due to structural defects. Then, we incorporate the vacancy defects and charge impurity effects in our Green's function based approach. Simulation results indicate decrease in average current due to the presence of such defects and impurities.

Keywords: carbon nanotube; field emission; electron-phonon; defect; impurity; transport

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