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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/19662

Title: Direct observation of electron emission from grain boundaries in CVD diamond by PeakForce-controlled tunnelling atomic force microscopy
Authors: Harniman, Robert L.
Fox, Oliver J. L.
Janssen, Wiebke
Drijkoningen, Sien
Haenen, Ken
May, Paul W.
Issue Date: 2015
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Citation: CARBON, 94, p. 386-395
Abstract: A detailed investigation of electron emission from a set of chemical vapour deposited (CVD) diamond films is reported using high-resolution PeakForce-controlled tunnelling atomic force microscopy (PF-TUNA). Electron field emission originates preferentially from the grain boundaries in low-conductivity polycrystalline diamond samples, and not from the top of features or sharp edges. Samples with smaller grains and more grain boundaries, such as nanocrystalline diamond, produce a higher emission current over a more uniform area than diamond samples with larger grain size. Light doping with N, B or P increases the grain conductivity, with the result that the emitting grain-boundary sites become broader as the emission begins to creep up the grain sidewalls. For heavy B doping, where the grains are now more conducting than the grain boundaries, emission comes from both the grain boundaries and the grains almost equally. Lightly P-doped diamond samples show emission from step-edges on the (111) surfaces. Emission intensity was time dependent, with the measured current dropping to similar to 10% of its initial value similar to 30 h after removal from the CVD chamber. This decrease is ascribed to the build-up of adsorbates on the surface along with an increase in the surface conductivity due to surface transfer doping. (C) 2015 The Authors. Published by Elsevier Ltd.
Notes: [Harniman, Robert L.; Fox, Oliver J. L.; May, Paul W.] Univ Bristol, Sch Chem, Bristol BS8 1TL, Avon, England. [Janssen, Wiebke; Drijkoningen, Sien; Haenen, Ken] Hasselt Univ, Inst Mat Res IMO, B-3590 Diepenbeek, Belgium. [Janssen, Wiebke; Haenen, Ken] IMEC VZW, IMOMEC, B-3590 Diepenbeek, Belgium.
URI: http://hdl.handle.net/1942/19662
DOI: 10.1016/j.carbon.2015.06.082
ISI #: 000360294900045
ISSN: 0008-6223
Category: A1
Type: Journal Contribution
Validation: ecoom, 2016
Appears in Collections: Research publications

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