Sp3/sp2 character of the carbon and hydrogen configuration in micro- and nanocrystalline diamond

Ballutaud, D.; Jomard, François; Kociniewski, T.; Rzepka, E.; Girard, Hugues A.; Saada, S.

doi:10.1016/j.diamond.2007.10.004

Cited by 70 publications

(54 citation statements)

References 10 publications

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“…It is well known that "as-grown" CVD polycrystalline diamond films exhibit p-type conductivity which can be removed by oxidation [11,12]. Ballutaud et al showed that the hydrogen concentration in polycrystalline diamond layer increases with increase of sp 2 /sp 3 ratio, and increase with decrease of crystallite sizes [13] which is in agreement with our observations (see Tables II and III). According to Zhang et al [14] chemically bonded hydrogen should govern the electrical properties of diamond layer.…”

Section: Methodssupporting

confidence: 82%

Structural and Electrical Characterization of Undoped Diamond Layer Grown by HF CVD

et al. 2017

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The undoped diamond layers were prepared using hot filament chemical vapor deposition technique. The controlled variation of the deposition parameters resulted in the layers with varying amount of nondiamond impurities. Routine characterization of the layers was carried out using scanning electron microscopy, X-ray diffractometry, and the Raman spectroscopy. Detailed measurements of room temperature electrical conductivity (σ300), currentvoltage characteristics have yielded useful information about the electrical conduction mechanism in this interesting material. The σ300 and I−V characteristic measurements were done in sandwiched configuration taking care off the surface effects. The diamond shows room temperature dc conductivity reaching the values in the range of σ300 ≈ 0.1−1 µS/cm. The I−V characteristics in these layers show space charge limited conduction behavior with I ∼ V 2 in high voltage region. The obtained results are explained in terms of chemically adsorbed hydrogen on the surface of diamond layers, which is a source of acceptor states just above the top of valence band.

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Section: Methodssupporting

confidence: 82%

Structural and Electrical Characterization of Undoped Diamond Layer Grown by HF CVD

et al. 2017

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“…The slope m of luminescence background is proportional to hydrogen concentration in CVD diamond film [10]. Because of higher slope m, the samples are characterized by higher hydrogen content which is mainly associated with existence of sp 2 carbon phase admixture which was also confirmed by earlier observation [11][12][13][14][15]. The influence of methane concentration on diamond quality is shown in Table 1.…”

Section: Resultssupporting

confidence: 58%

Impedance study of undoped, polycrystalline diamond layers obtained by HF CVD

et al. 2017

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passivation layers. These films can be deposited by several techniques, such as Hot Filament Chemical Vapour Deposition (HF CVD), Microwave Plasma CVD (MP CVD), Plasma Jet CVD, or Flame CVD [2].The film characteristics depend on several different deposition process parameters, such as the gas composition and pressure, the substrate temperature, the energy of the impinging ions, etc [3]. The presence of hydrogen in the gas phase promotes the formation of sp 3 C structures but co-deposition of sp 2 carbon phase, as detected by Raman spectroscopy, also takes place [4].Due to its superior physical and chemical properties, diamond can be used as an electronic or optoelectronic material because of its high Johnson and Keyes figures of merit values [5]. However, the electrical and optical properties of diamond films strongly depend on the film preparation conditions. Compared with natural diamond, CVD diamond is usually polycrystalline and contains various defects produced during the deposition procedure. Therefore, it is necessary to establish the relationship between the preparation conditions and the structural and electrical properties of diamond films for electronic or optoelectronic applications.In general, polycrystalline diamond films can be considered as composed from diamond microcrystals oriented in different direction with respect to the substrate surface. The quality of diamond layers increases as the grain size increases starting from the substrate nucleation side to the top of the diamond layer [6].The larger grains induce a decrease of GB phase in the film what results that diamond layer will have smaller content of the sp 2 -hybridized carbon phase. The sizes of grain boundaries and thus concentration of sp 2 carbon phase eventually can lead to limitations in electronic performances of polycrystalline diamond layers. AbstractIn this paper, we report results of impedance measurements in polycrystalline diamond films deposited on n-Si using HF CVD method. The temperature was changed from 170 K up to RT and the scan frequency from 42 Hz to 5 MHz. The results of impedance measurement of the real and imaginary parts were presented in the form of a Cole-Cole plot in the complex plane. In the temperatures below RT, the observed impedance response of polycrystalline diamond was in the form of a single semicircular form. In order to interpret the observed response, a double resistor-capacitor parallel circuit model was used which allow for interpretation physical mechanisms responsible for such behavior. The impedance results were correlated with Raman spectroscopy measurements.

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“…Hydrogen's high mobility and bonding may release accumulated stress in carbon layers, [27][28][29] as well as in other materials. 30 It was shown previously, 26,[31][32][33][34][35][36][37][38][39][40] that polycrystalline CVD diamond film deposited in a hydrogen containing atmosphere ͑even from an H deficient/Ar rich gas phase with ϳ1% H 2 ͒ contains up to a few at. % of hydrogen atoms.…”

Section: Introductionmentioning

confidence: 99%

Bulk and surface thermal stability of ultra nanocrystalline diamond films with 10–30 nm grain size prepared by chemical vapor deposition

Michaelson

Stacey

Orwa

et al. 2010

Journal of Applied Physics

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The thermal stability of nanocrystalline diamond films with 10–30 nm grain size deposited by microwave enhanced chemical vapor deposition on silicon substrate was investigated as a function of annealing temperature up to 1200 °C. The thermal stability of the surface-upper atomic layers was studied with near edge x-ray absorption fine structure (NEXAFS) spectroscopy recorded in the partial electron yield mode. This technique indicated substantial thermally induced graphitization of the film within a close proximity to the surface. While in the bulk region of the film no graphitization was observed with either Raman spectroscopy or NEXAFS spectroscopy recorded in total electron yield mode, even after annealing to 1200 °C. Raman spectroscopy did detect the complete disappearance of transpolyacetylene (t-PA)-like ν1 and ν3 modes following annealing at 1000 °C. Secondary ion mass spectroscopy, applied to investigate this relative decrease in hydrogen atom concentration detected only a ∼30% decrease in the bulk content of hydrogen atoms. This enhanced stability of sp3 hybridized atoms within the bulk region with respect to graphitization is discussed in terms of carbon bond rearrangement due to the thermal decomposition of t-PA-like fragments.

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Sp3/sp2 character of the carbon and hydrogen configuration in micro- and nanocrystalline diamond

Cited by 70 publications

References 10 publications

Structural and Electrical Characterization of Undoped Diamond Layer Grown by HF CVD

Structural and Electrical Characterization of Undoped Diamond Layer Grown by HF CVD

Impedance study of undoped, polycrystalline diamond layers obtained by HF CVD

Bulk and surface thermal stability of ultra nanocrystalline diamond films with 10–30 nm grain size prepared by chemical vapor deposition

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