Local electric field and enhancement factor around nanographitic structures embedded in amorphous carbon

Kokkorakis, GC; Xanthakis, JP

dc.contributor.author	Kokkorakis, GC	en
dc.contributor.author	Xanthakis, JP	en
dc.date.accessioned	2014-03-01T02:44:49Z
dc.date.available	2014-03-01T02:44:49Z
dc.date.issued	2007	en
dc.identifier.issn	0142-2421	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/31951
dc.subject	Amorphous carbon	en
dc.subject	Field emission	en
dc.subject	Local field	en
dc.subject	Nanographitic structures	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	Amorphous materials	en
dc.subject.other	Binding energy	en
dc.subject.other	Electric fields	en
dc.subject.other	Field emission cathodes	en
dc.subject.other	Mathematical models	en
dc.subject.other	Molecular dynamics	en
dc.subject.other	Nanostructured materials	en
dc.subject.other	Amorphous carbon	en
dc.subject.other	Enhancement factors	en
dc.subject.other	Local field	en
dc.subject.other	Nanographitic structures	en
dc.subject.other	Graphite	en
dc.title	Local electric field and enhancement factor around nanographitic structures embedded in amorphous carbon	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1002/sia.2476	en
heal.identifier.secondary	http://dx.doi.org/10.1002/sia.2476	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	Amorphous pure sp2 bonding carbon films are believed to contain elongated or columnar regions of graphitic character. Although these regions must be very rare, as all molecular dynamics simulations show, they have a profound effect on the field emission capability of this flat material because they provide an internal field-enhancement mechanism. In this paper, we calculate the internal local field around such columnar regions, with the additional restriction that they do not make contact with the cathode; otherwise the problem has a well-known solution. Our problem is physically and mathematically more complicated, as now the 'metallic region' surface is not equipotential with the cathode. We have managed to solve it by requiring that the total charge on the columnar metallic structure is zero. Our findings show that such regions produce an enhancement factor that is a fraction (typically 0.5) of the known ratio h/r (h = height and r = radius). As these structures become longer and approach the cathode, this fraction increases towards unity, but not linearly. A sudden jump occurs when contact with the cathode is established. The most interesting result is the following: Just before contact with the cathode, the local field at the cathode-facing end of such a structure increases considerably above the value h/r. The physical ramifications of these results are discussed, especially in relation to emission onset. Copyright © 2007 John Wiley & Sons, Ltd.	en
heal.publisher	JOHN WILEY & SONS LTD	en
heal.journalName	Surface and Interface Analysis	en
dc.identifier.doi	10.1002/sia.2476	en
dc.identifier.isi	ISI:000244295600011	en
dc.identifier.volume	39	en
dc.identifier.issue	2-3	en
dc.identifier.spage	135	en
dc.identifier.epage	138	en