Design and properties of low-energy X-ray transmission windows based on graphenic carbon

Huebner, Sebastian; Miyakawa, Natsuki; Pahlke, Andreas; Kreupl, Franz

doi:10.1002/pssb.201552216

Cited by 15 publications

(9 citation statements)

References 45 publications

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“…Bulge testing was performed in order to approximate the Young's modulus of the window material. The procedure and limitations of this method are discussed in detail in reference [2]. Figure 3 shows the results of bulge testing performed with a GC window with a thickness of 710 nm and a diameter of 7.31 mm.…”

Section: Resultsmentioning

confidence: 99%

“…Graphenic carbon (GC) is a suitable window material that outperforms beryllium (Be) x-ray transmission windows in regard to the x-ray transmission and cycle stability, while avoiding the health concerns of Be [1]. A substrate design incorporating silicon (Si) support bars allows sufficiently thin GC windows that result in an excellent transmission for low energy x-ray radiation with an improved transmission of the carbon Kα line compared to available low energy transmission windows based on silicon nitride and polymers [2,3,4].…”

Section: Introductionmentioning

confidence: 99%

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Performance Improvement of Graphenic Carbon X-ray Transmission Windows

Huebner

Miyakawa²,

Pahlke³

et al. 2016

MRS Advances

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Graphenic carbon (GC) x-ray transmission windows for EDX and XRF applications with a high transparency for x-rays below 2.5 keV have been fabricated on 6 inch wafers with a CMOS-compatible CVD process. GC windows with an open diameter of 7.4 mm and a thickness of 770 nm withstand up to 6.5 bars of differential pressure. A high transmissivity of 40 % for fluorine Kα (0.677 keV) radiation is demonstrated for a GC thickness of 650 nm. The GC membranes outperform beryllium (Be) windows, in terms of higher x-ray transmission and better mechanical stability while avoiding the toxicity of Be. Optical profilometry has been employed to visualize a large deformation of the GC layer during the window fabrication. This seems to limit the thickness of the GC windows that can currently be fabricated. A two-step growth process can overcome these limitations and windows with a thickness of up to 6 μm have been realized.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance Improvement of Graphenic Carbon X-ray Transmission Windows

Huebner

Miyakawa²,

Pahlke³

et al. 2016

MRS Advances

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“…10) indicating that the 60 mm 2 SDD was also equipped with the AP3.3 window. However, next-generation detectors will be equipped with the new polymer, Si 3 N 4 and perhaps graphene (Huebner et al, 2015) windows. The test material EDS-TM002 can be applied to identify next-generation windows by comparing line intensity ratios.…”

Section: Discussionmentioning

confidence: 99%

Determination of the Effective Detector Area of an Energy-Dispersive X-Ray Spectrometer at the Scanning Electron Microscope Using Experimental and Theoretical X-Ray Emission Yields

et al. 2016

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A method is proposed to determine the effective detector area for energy-dispersive X-ray spectrometers (EDS). Nowadays, detectors are available for a wide range of nominal areas ranging from 10 up to 150 mm2. However, it remains in most cases unknown whether this nominal area coincides with the "net active sensor area" that should be given according to the related standard ISO 15632, or with any other area of the detector device. Moreover, the specific geometry of EDS installation may further reduce a given detector area. The proposed method can be applied to most scanning electron microscope/EDS configurations. The basic idea consists in a comparison of the measured count rate with the count rate resulting from known X-ray yields of copper, titanium, or silicon. The method was successfully tested on three detectors with known effective area and applied further to seven spectrometers from different manufacturers. In most cases the method gave an effective area smaller than the area given in the detector description.

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“…The substrate is either a 3 mm thick glassy carbon (Hochtemperatur Werkstoffe GmbH SIGRADUR ® G) or a 220 nm thick graphenic carbon layer directly grown by chemical vapor deposition (CVD) on a Si substrate [52]. Both working electrodes are characterized by atomic force microscopy, -Raman spectroscopy and cyclic voltammetry with 1 M H 2 SO 4 as electrolyte to exclude parasitic effects to our measurements on the MoS 2 flakes.…”

Section: Preparation Of the Pec -Cellmentioning

confidence: 99%

Hydrogen evolution activity of individual mono-, bi-, and few-layer MoS 2 towards photocatalysis

Parzinger

Mitterreiter

Stelzer

et al. 2017

Applied Materials Today

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b s t r a c tWe investigate the hydrogen evolution activity in the dark and under illumination above the band gap of individual mono-, bi-and few-layer (bulk) MoS 2 flakes. We demonstrate that the electrocatalytic activity of 2H-MoS 2 immersed in 1 M H 2 SO 4 increases with decreasing number of layers. For monolayers, we observe the highest exchange current density, which is one magnitude larger than in the bulk case. The onset potential scales with the number of layers, which is consistent with a previous report, suggesting that hopping transport across inter-layer barriers within the MoS 2 flakes is responsible for this scaling.A specially designed micro-sized catalytic cell enables us to investigate individual MoS 2 flakes with well-known geometry and edge-to-surface ratio. Taking these geometric parameters into account, we tentatively attribute the catalytic activity mainly to sulfur vacancies in the basal planes acting as active sites. The associated turn over frequencies (TOF) for mono-and bi-layer MoS 2 yield values higher than 10 3 s −1 at an overpotential of −0.2 V vs. RHE. In view of light driven hydrogen evolution as a means of solar energy conversion, we investigate the photocatalytic activity of few-layer MoS 2 under white light illumination.

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Design and properties of low-energy X-ray transmission windows based on graphenic carbon

Cited by 15 publications

References 45 publications

Performance Improvement of Graphenic Carbon X-ray Transmission Windows

Performance Improvement of Graphenic Carbon X-ray Transmission Windows

Determination of the Effective Detector Area of an Energy-Dispersive X-Ray Spectrometer at the Scanning Electron Microscope Using Experimental and Theoretical X-Ray Emission Yields

Hydrogen evolution activity of individual mono-, bi-, and few-layer MoS 2 towards photocatalysis

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