Theory of electron energy loss spectroscopy and its application to threading edge dislocations in GaN

Fall, CJ, Jones, R, Briddon, PR, Blumenau, AT, Frauenheim, T and Heggie, MI (2002) Theory of electron energy loss spectroscopy and its application to threading edge dislocations in GaN Materials Research Society Symposium - Proceedings, 693. pp. 585-595.

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Abstract

The electronic structure of dislocations in GaN is controversial. Several experimental techniques such as carrier mobility studies and cathodoluminescence experiments have indicated that dislocations are charged while theoretical studies point to intrinsic states and/or point defect accumulation along the core as a source of electrical activity. Electron Energy Loss Spectroscopy (EELS) studies have the ability to probe the electronic structure of extended defects. Here we report first principles calculations of the EELS spectrum applied to edge dislocations in GaN. It is found that the electrostatic potential at N atoms in the vicinity of the dislocation varies by the order of a volt and casts doubt on any simple interpretation of core loss spectroscopy. On the other hand, low loss spectroscopy leads directly to detailed information about any gap states. The low loss spectrum obtained by the theory is in good agreement with recent experimental work and indicates that threading dislocations in p-type GaN possess acceptor levels in the upper half of the gap.

Item Type:	Article
Divisions :	Surrey research (other units)
Authors :	Name Email ORCID Fall, CJ Jones, R Briddon, PR Blumenau, AT Frauenheim, T Heggie, MI m.heggie@surrey.ac.uk
Date :	1 January 2002
Depositing User :	Symplectic Elements
Date Deposited :	17 May 2017 12:42
Last Modified :	24 Jan 2020 22:43
URI:	http://epubs.surrey.ac.uk/id/eprint/836443

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