Angular variation of the transmission coefficient of electrons from open carbon nanotubes by a 3-dimensional WKB method

Xanthakis, JP; Kokkorakis, GC; Sfakianakis, EI

dc.contributor.author	Xanthakis, JP	en
dc.contributor.author	Kokkorakis, GC	en
dc.contributor.author	Sfakianakis, EI	en
dc.date.accessioned	2014-03-01T01:27:56Z
dc.date.available	2014-03-01T01:27:56Z
dc.date.issued	2008	en
dc.identifier.issn	1386-9477	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18640
dc.subject	Barrier potential	en
dc.subject	Carbon nanotubes	en
dc.subject	Field emission	en
dc.subject	Transmission coefficient	en
dc.subject	WKB	en
dc.subject.classification	Nanoscience & Nanotechnology	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	Computational geometry	en
dc.subject.other	Field emission	en
dc.subject.other	Three dimensional	en
dc.subject.other	Angular variation	en
dc.subject.other	Barrier potentials	en
dc.subject.other	Transmission coefficient	en
dc.subject.other	Carbon nanotubes	en
dc.title	Angular variation of the transmission coefficient of electrons from open carbon nanotubes by a 3-dimensional WKB method	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.physe.2007.10.087	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.physe.2007.10.087	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	We have calculated by a 3-dimensional (3D) WKB method the transmission coefficient T(theta) of open carbon nanotubes (CNTs) as a function of the angle 0 and the geometry of the tube, namely the height h, the radius R and the thickness w of a CNT. For the potential barriers we have used the results of our previous work [G.C. Kokkorakis, J.A. Roumeliotis, J.P. Xanthakis, J. Appl. Phys. 95 (2004) 1468]. For the calculation of T(theta) we have used the method of Das and Mahanty [Phys. Rev. B 36 (1987) 898], which is a 3D generalization of the traditional one-dimensional (1D) WKB method. Due to the open shape of the tube and its nanometric scale we have found considerable deviations of T(theta) from the ID WKB theory. In particular, the paths of the emitted electrons are highly curved at certain directions theta. In addition T(theta) has contributions predominately from the outer wall of a CNT due to the asymmetry of the barrier potential. These two factors will definitely affect the direction of the emitted current. Such a phenomenon does not occur with closed CNTs. Furthermore, we have established that an increase in the magnitude of the T(theta) (by the use e.g., of a higher tube or higher applied voltage) will result in a T(theta) which will be more asymmetric with respect to angle. (c) 2007 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Physica E: Low-Dimensional Systems and Nanostructures	en
dc.identifier.doi	10.1016/j.physe.2007.10.087	en
dc.identifier.isi	ISI:000254371200025	en
dc.identifier.volume	40	en
dc.identifier.issue	4	en
dc.identifier.spage	873	en
dc.identifier.epage	877	en