Field penetration into amorphous-carbon films: Consequences for field-induced electron emission

Forbes, RG; Xanthakis, JP

dc.contributor.author	Forbes, RG	en
dc.contributor.author	Xanthakis, JP	en
dc.date.accessioned	2014-03-01T02:44:37Z
dc.date.available	2014-03-01T02:44:37Z
dc.date.issued	2007	en
dc.identifier.issn	0142-2421	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/31916
dc.subject	Amorphous carbon	en
dc.subject	Field emission	en
dc.subject	Field penetration	en
dc.subject	Hopping conductors	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	Carbon	en
dc.subject.other	Electron emission	en
dc.subject.other	Energy gap	en
dc.subject.other	Mathematical models	en
dc.subject.other	Poisson equation	en
dc.subject.other	Semiconducting films	en
dc.subject.other	Amorphous carbon	en
dc.subject.other	Field penetration	en
dc.subject.other	Hopping conductors	en
dc.subject.other	Low-macroscopic-field (LMF)	en
dc.subject.other	Amorphous films	en
dc.title	Field penetration into amorphous-carbon films: Consequences for field-induced electron emission	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1002/sia.2477	en
heal.identifier.secondary	http://dx.doi.org/10.1002/sia.2477	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	The phenomenon of low-macroscopic-field (LMT) electron emission is sometimes exhibited by thin films of non-metallic materials. Both wide-band-gap semiconductors and hopping conductors such as amorphous carbon exhibit this phenomenon, and its origin has been under discussion for some years. This paper first uses a simple theory to discuss field penetration into hopping conductors with a high density of localised states near the charge-neutrality level. This theory is physically similar to widely used existing theories, in that it assumes continuous charge distributions and uses the one-dimensional Poisson's equation. The theory suggests that little field penetration occurs, and that models of LMF emission based on uniform barrier lowering are not viable. Unexpected self-consistency difficulties are also created for some types of local-field-enhancement model. A re-assessment of the validity of this simple field-penetration theory suggests the following. Contrary to a basic assumption of this type of theory, the granularity of the screening charge distribution is a dominant feature of the physics associated with LMF emission from nanoscale-sized emission sites on thin films of hopping conductors. The authors think that the screening is carried out by discrete charges in localised states, although details are not clear. This conclusion is potentially very far-reaching. In particular, new forms of field-penetration theory may be required before definitive decisions can be made about the self-consistency of some models of local field enhancement. Copyright (C) 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.2477	en
dc.identifier.isi	ISI:000244295600012	en
dc.identifier.volume	39	en
dc.identifier.issue	2-3	en
dc.identifier.spage	139	en
dc.identifier.epage	145	en