Cathodoluminescence (CL) and CL spectra of De Beers’ experimental synthetic diamonds

Ponahlo, Johann

doi:10.15506/jog.1992.23.1.3

“…The three faceted stones displayed cathodoluminescence when they were exposed to an electron beam. This luminescence was quite intense, andas has been noted in previous studes of synthetic diamonds (Woods and Lang, 1975;Shigley et al, 1987;Ponahlo, 1992)-it was also zoned in color and intensity (see table 1). To the unaided eye, the luminescence appears yellow, but photography recorded more blue than yellow for one sample (figure 2).…”

Section: Observationssupporting

confidence: 81%

De Beers Near Colorless-to-Blue Experimental Gem-Quality Synthetic Diamonds

Rooney¹,

Welbourn²,

Shigley³

et al. 1993

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Examination offive small Boron-doped synthetic diamonds, grown by De Beers researchers for experimental purposes, reveals some diagnostic &atures not reported in previous studies of gemquality synthetic diamonds. The presence of internal growth sectors that are blue, yellow, or near colorless has produced faceup colors in three faceted stones that vary fiom near colorless to bluishgreenish gray to blue. Because they look so dzferent fiom previously reported De Beers synthetic diamonds, such faceted synthetics could go unrecognized without carebl gemological testing should they ever become commercially available.Previous articles on gem-quality synthetic diamonds have reported the visible zoning of certain features such as color, ultraviolet luminescence, and graining, and their importance as identification criteria for t h s materd (see Slugley et al., 1986Slugley et al., , 1987Slugley et al., , 1992. Recently, we examined two small crystals (0.12 and 0.20 ct) and three faceted De Beers synthetic diamonds (0.05 to 0.07 ct) that are interesting examples of a lund of internal color zoning that produces a variable overall color appearance (figure 1

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“…Several papers demonstrate the secondary electron images and the corresponding spectrally resolved CL images of homoepitaxial layer on HP diamond (Katsumata 1992), CVD diamond particles , CVD diamond films (Muranaka et al 1991, Yacobi et al 1991, polycrystalline diamond (Lang 1993) and natural diamonds (Frank 1990;Lang and Meaden 1991;Ponachlo 1992;Welborn et al 1981;Zezin et al 1990Zezin et al , 1992. The difference of the luminescence regions has also been observed in CL images taken with 440 nm (2.82 eV) and 530 nm (2.34 eV) signals .…”

Section: Recognition Of Defects (Cathodoluminescence Mode Of the Sem)mentioning

confidence: 91%

Morphologic and cathodoluminescence studies of diamond films by scanning electron microscopy

Saparin

¹

,

Obyden

²

1995

Scanning

3

0

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Summary: Using recent papers on scanning electron microscopy (SEM) of chemical vapor deposition (CVD) diamond films, two analytical applications of the SEM are discussed: the morphologic investigations (secondary electron emission mode) and the recognition of impurities and defects [cathodoluminescence (CL) mode]. Studies of CVD diamond films by SEM demonstrate that the morphologies of these films are affected by synthesis conditions, especially by substrate temperature, methane concentration, and total pressure in the reactor. CL spectra and images are useful tools for clarifying the relationship between emission centers and different types of defects generated during the process of diamond crystal growth. The paper shows that the investigations of the morphology, crystallinity, local CL emission, as well as the surface distribution of CL spectra on CVD diamond films by SEM led to the correlative information for quality estimation of films in comparison with natural diamond.

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“…On the other hand, relative impurities of nitrogen and silicon were easily incorporated into the (131) and (141) planes. The author identified centers as follows: (111) and (010) Several papers demonstrate the secondary electron images and the corresponding spectrally resolved CL images of homoepitaxial layer on HP diamond (Katsumata 1992), CVD diamond particles , CVD diamond films (Muranaka et al 1991, Yacobi et al 1991, polycrystalline diamond (Lang 1993) and natural diamonds (Frank 1990;Lang and Meaden 1991;Ponachlo 1992;Welborn et al 1981;Zezin et al 1990Zezin et al , 1992. The difference of the luminescence regions has also been observed in CL images taken with 440 nm (2.82 eV) and 530 nm (2.34 eV) signals .…”

Section: Recognition Of Defects (Cathodoluminescence Mode Of the Sem)mentioning

confidence: 99%

“…However, nowadays a black/white contrast used in the CL-SEM technique loses much local information (about a factor of 100 in the binary code system) in comparison with real color contrast used in the CCL-SEM and luminoscope techniques Ponachlo 1992;Obyden 1988, 1994;). Up-to-date color CL-SEM techniques use a stationary defocused electron beam that floods the specimen surface of interest which is then photographed by a camera or TV viewing system (Lang and Meaden 1991).…”

Section: Recognition Of Defects (Cathodoluminescence Mode Of the Sem)mentioning

confidence: 99%

Untitled

1995

Scanning

0

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Summary: Using recent papers on scanning electron microscopy (SEM) of chemical vapor deposition (CVD) diamond films, two analytical applications of the SEM are discussed: the morphologic investigations (secondary electron emission mode) and the recognition of impurities and defects [cathodoluminescence (CL) mode]. Studies of CVD diamond films by SEM demonstrate that the morphologies of these films are affected by synthesis conditions, especially by substrate temperature, methane concentration, and total pressure in the reactor. CL spectra and images are useful tools for clarifying the relationship between emission centers and different types of defects generated during the process of diamond crystal growth. The paper shows that the investigations of the morphology, crystallinity, local CL emission, as well as the surface distribution of CL spectra on CVD diamond films by SEM led to the correlative information for quality estimation of films in comparison with natural diamond.

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Cathodoluminescence (CL) and CL spectra of De Beers’ experimental synthetic diamonds

Cited by 16 publications

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De Beers Near Colorless-to-Blue Experimental Gem-Quality Synthetic Diamonds

De Beers Near Colorless-to-Blue Experimental Gem-Quality Synthetic Diamonds

Morphologic and cathodoluminescence studies of diamond films by scanning electron microscopy

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