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dc.contributor.authorCuenca, Jerome Alexander
dc.contributor.authorThomas, Evan
dc.contributor.authorMandal, Soumen
dc.contributor.authorMorgan, David John
dc.contributor.authorLloret Vieira, Fernando Manuel 
dc.contributor.authorAraújo Gay, Daniel 
dc.contributor.authorWilliams, Oliver Aneurin
dc.contributor.authorPorch, Adrian
dc.contributor.otherCiencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánicaen_US
dc.date.accessioned2018-12-03T11:42:44Z
dc.date.available2018-12-03T11:42:44Z
dc.date.issued2018
dc.identifier.issn2470-1343
dc.identifier.urihttp://hdl.handle.net/10498/20911
dc.description.abstractMicrowave dielectric loss tangent measurements are demonstrated as a method for quantifying trace sp2-hybridized carbon impurities in sub-micron diamond powders. Appropriate test samples are prepared by vacuum annealing at temperatures from 600 to 1200 °C to vary the sp2/sp3 carbon ratio through partial surface graphitization. Microwave permittivity measurements are compared with those obtained using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electron energy loss spectroscopy (EELS). The average particle size remains constant (verified by scanning electron microscopy) to decouple any geometric dielectric effects from the microwave measurements. After annealing, a small increase in sp2 carbon was identified from the XPS C 1s and Auger spectra, the EELS σ* peak in the C 1s spectra, and the D and G bands in Raman spectroscopy, although a quantifiable diamond to G-band peak ratio was unobtainable. Surface hydrogenation was also evidenced in the Raman and XPS O 1s data. Microwave cavity perturbation measurements show that the dielectric loss tangent increases with increasing sp2 bonding, with the most pertinent finding being that these values correlate with other measurements and that trace concentrations of sp2 carbon as small as 5% can be detected.en_US
dc.formatapplication/pdfen_US
dc.language.isoengen_US
dc.publisherACS Publicationsen_US
dc.rightsAtribución 4.0 Internacional*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.sourceACS Omega 2018,3, 2183-2192en_US
dc.titleMicrowave Permittivity of Trace sp² Carbon Impurities in Sub-Micron Diamond Powdersen_US
dc.typeinfo:eu-repo/semantics/articleen_US
dc.rights.accessRightsinfo:eu-repo/semantics/openAccessen_US
dc.identifier.doi10.1021/acsomega.7b02000


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Atribución 4.0 Internacional
This work is under a Creative Commons License Atribución 4.0 Internacional