Effects of hydrogen termination of CVD diamond layers

Mosińska, L.; Popielarski, P.; Fabisiak, K.; Dychalska, Anna

doi:10.1016/j.optmat.2020.109676

Cited by 16 publications

(11 citation statements)

References 24 publications

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“…Hydrogen is believed to saturate non-radiative recombination sites like dangling bonds and, as a result, form centres of radiative recombination. Therefore, m/I G parameter may indicate the concentration of hydrogen in diamond layer [ 29 , 30 , 31 ].…”

Section: Resultsmentioning

confidence: 99%

“…Additional information can be also extracted from the photoluminescence PL background of the Raman spectrum, as it has been shown that the slope m of the linearly subtracted PL background normalized to the intensity of G band— m/I G is proportional to the hydrogen concentration in hydrogenated amorphous carbon [ 29 ]. It has also been shown that the PL background of Raman spectra of diamond layers depends on the hydrogen concentration at grain boundaries and on the surface [ 30 , 31 ]. However, density of defects in the diamond layer also influences the PL background behaviour and possible changes in m/I G parameter might be very small; therefore, data interpretation must be performed with caution.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Surface Treatment on Structural Properties of CVD Diamond Layers with Different Grain Sizes Studied by Raman Spectroscopy

et al. 2021

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Extensive Raman spectroscopy studies combined with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) measurements were performed to investigate structural and chemical changes in diamond layers deposited by chemical vapour deposition (CVD) upon post-growth treatment with hydrogen. The aim of this study is to characterize the changes in micro-structural properties of diamond layers with different grain sizes and different contents of sp2 carbon phase. Hydrogenation or oxidization of diamond layer surface is often performed to modify its properties; however, it can also strongly affect the surface structure. In this study, the impact of hydrogenation on the structure of diamond layer surface and its chemical composition is investigated. Owing to their polycrystalline nature, the structural properties of CVD diamond layers can strongly differ within the same layer. Therefore, in this project, in order to compare the results before and after hydrogen treatment, the diamond layers are subjected to Raman spectroscopy studies in the vicinity of a T-shape marker fabricated on the surface of each diamond layer studied.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Surface Treatment on Structural Properties of CVD Diamond Layers with Different Grain Sizes Studied by Raman Spectroscopy

et al. 2021

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“…The PDD sample was later exposed to atmosphere when partially hydrogen terminated before being tested again, significantly reducing its emission intensity. Contact angle measurements of a hydrogen desorbed sample after air exposure shows contact angles of about 65 , indicating a significantly decreased hydrophobicity after removal of hydrogen [11,12], compared with the contact angle of hydrogen terminated diamond in Fig. S1.…”

Section: Resultsmentioning

confidence: 97%

“…All samples were then hydrogen terminated using the MWPECVD reactor using 300 SCCM of H 2 at 800 C and 500 C for 2 min each. The hydrogen termination was confirmed using contact angle measurements [11,12], showing angles of about 100 in Fig. S1.…”

Section: Methodsmentioning

confidence: 96%

Spectroscopic insight of low energy electron emission from diamond surfaces

Wan

Cattelan

Croot

et al. 2021

Carbon

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Low work function materials are desirable in many applications such as electron emission and photocatalysis. We have studied low energy electron emission from low work function hydrogen terminated diamond surfaces via electron spectroscopy to gain insight into the mechanisms involved during electron excitation and emission. Electron emission was found to be dominated by electrons within the band gap energy region, allowed due to the negative electron affinity diamond surface, while sub-bandgap illumination was able to significantly increase emission current. Substantial upward surface band bending greater than 2 eV was observed for the diamond samples, which affect electron accumulation at the surfaces. Intra-bandgap states are shown to strongly influence electron emission behavior, which can have great implications for various energy conversion devices.

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“…7 µm into the rod’s surface. Additionally, calculation of the m / I G parameter (where m is the slope of the linear photoluminescence background, while I G is the intensity of the G band), which is used for the estimation of hydrogen content from Raman spectra (for example [ 30 , 31 ]), was 5–6 times higher in value for coated ZIRLO rods treated in the hot steam at 850 °C than after the 1000 °C steam treatment, as discussed in the Supplementary Material S1 .…”

Section: Resultsmentioning

confidence: 99%

Diamond Coating Reduces Nuclear Fuel Rod Corrosion at Accidental Temperatures: The Role of Surface Electrochemistry and Semiconductivity

et al. 2021

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If we want to decrease the probability of accidents in nuclear reactors, we must control the surface corrosion of the fuel rods. In this work we used a diamond coating containing <60% diamond and >40% sp2 “soft” carbon phase to protect Zr alloy fuel rods (ZIRLO ®) against corrosion in steam at temperatures from 850 °C to 1000 °C. A diamond coating was grown in a pulse microwave plasma chemical vapor deposition apparatus and made a strong barrier against hydrogen uptake into ZIRLO® (ZIRLO) under all tested conditions. The coating also reduced ZIRLO corrosion in hot steam at 850 °C (for 60 min) and at 900 °C (for 30 min). However, the protective ability of the diamond coating decreased after 20 min in 1000 °C hot steam. The main goal of this work was to explain how diamond and sp2 “soft” carbon affect the ZIRLO fuel rod surface electrochemistry and semi conductivity and how these parameters influence the hot steam ZIRLO corrosion process. To achieve this goal, theoretical and experimental methods (scanning electron microscopy, Raman spectroscopy, electrochemical impedance spectroscopy, carrier gas hot extraction, oxidation kinetics, ab initio calculations) were applied. Deep understanding of ZIRLO surface processes and states enable us to reduce accidental temperature corrosion in nuclear reactors.

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Effects of hydrogen termination of CVD diamond layers

Cited by 16 publications

References 24 publications

The Effect of Surface Treatment on Structural Properties of CVD Diamond Layers with Different Grain Sizes Studied by Raman Spectroscopy

The Effect of Surface Treatment on Structural Properties of CVD Diamond Layers with Different Grain Sizes Studied by Raman Spectroscopy

Spectroscopic insight of low energy electron emission from diamond surfaces

Diamond Coating Reduces Nuclear Fuel Rod Corrosion at Accidental Temperatures: The Role of Surface Electrochemistry and Semiconductivity

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