Direct Observations of Crystal Defects in Polycrystalline Diamond

Document Type

Article

Publication Date

5-23-2018

Publication Title

Materials Characterization

Volume

142

First page number:

154

Last page number:

161

Abstract

Crystal defects are abundant in synthetic diamond produced by chemical vapor deposition (CVD). We present the first images of crystal defects in a bulk polycrystalline CVD diamond sample using general electron channeling contrast imaging (ECCI) in a field emission scanning electron microscope (FE-SEM). For enhancement of channeling contrast of this material, we introduce a novel protocol for diamond surface preparation that involves acid etching. Using this protocol, we imaged three types of crystal defects including twins, stacking faults and dislocations. Each defect was identified based on its appearance in electron channeling contrast (ECC) micrographs. We analyzed grains containing twins and dislocations using electron backscatter diffraction (EBSD) crystal orientation mapping. We found a large population of grains that contained Σ3 type twins on {111} planes with a 60°〈111〉 angle–axis pair of misorientation for twin boundaries. In addition, we identified {111} stacking faults and {111} helical dislocations. These observations are in agreement with reports of crystal defects in CVD diamond thin foils studied by a transmission electron microscope (TEM).

Keywords

Chemical vapor deposition (CVD) diamond; Electron channeling contrast imaging (ECCI); Electron backscatter diffraction (EBSD); Twins; Stacking faults; Dislocations; Etching

Disciplines

Earth Sciences

Language

English

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