Optical excitation of paramagnetic nitrogen in chemical vapor deposited diamond

Graeff, Carlos F. O.; Rohrer, E.P.; Nebel, Christoph E.; Stutzmann, M.; Güttler, H.; Zachai, R.

doi:10.1063/1.117965

Cited by 30 publications

(16 citation statements)

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“…Our previous EPR study of CVD diamond showed that nitrogen is incorporated mainly into CVD diamond as a substitutional-nitrogen defect (P1 center), and that other various aggregate forms do not exist (15,22). The substitution incorporation of nitrogen results in distortion of the diamond lattice and the observed transition from ͗111͘-to-͗100͘ growth habit in the film.…”

mentioning

confidence: 99%

Very high growth rate chemical vapor deposition of single-crystal diamond

Yan

Vohra

Mao

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

235

109

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Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of highquality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to that of high-pressure, high-temperature synthetic diamond. In addition, the crystals can be produced at growth rates from 50 to 150 m͞h, which is up to 2 orders of magnitude higher than standard processes for making polycrystalline MPCVD diamond. This high-quality single-crystal MPCVD diamond may find numerous applications in electronic devices as high-strength windows and in a new generation of high-pressure instruments requiring large single-crystal anvils. Diamond produced by low-pressure microwave plasma (MP) chemical vapor deposition (CVD) is the most promising technology for producing low-cost and high-quality large diamond (1, 2). Nevertheless, the widespread use of MPCVD diamond in many applications has not been successful due to the existence of grain boundaries of polycrystalline diamond that are produced and slow growth rates, typically 1 m͞h (1-7). Diamond's strong covalent bonds and rigid structure (8) give rise to its unique properties. Diamond is the hardest and stiffest material known, has the highest room-temperature thermal conductivity and one of the lowest thermal expansion of known materials, and is radiation-hard and chemically inert to most acidic and basic reagents. Due to the high cost, limited size, and uneasily controlled impurities of natural and synthetic highpressure, high-temperature (HPHT) diamond, the applications of diamond have in fact been limited in comparison to its great potential (8). Thus, CVD diamond is the most promising avenue available for synthetic diamond. The major CVD diamondcoating techniques are the hot-filament, radio-frequency plasma, MP, and arcjet-torch methods (8, 9). Comparing these techniques, MPCVD-reactor methods provide stable conditions, reproducible sample quality, and reasonable cost (8, 9). In fact, steady progress in MPCVD synthesis techniques has made it possible to manufacture high-quality polycrystalline CVDdiamond optical components (4, 10), but this polycrystalline material consists of a patchwork of tiny crystals welded to one another along misaligned grain boundaries, which block the flow of current (10-12). The major disadvantage of MPCVD using 12.2 cm͞2.54 GHz for plasma generation is the lower growth rate, typically 1 m͞h (1-7) compared with arcjet torches; moreover at several hundred micrometers per hour (13), the plasma tends to concentrate at tips and edges (9, 13). Here we show that MPCVD diamond can be produced as high-quality and high growth rate (50-150 m depending on stage design and methane concentration) single crystals for a variety of purposes including the enlargement of anvils (14) for compressing large samples at ultrahigh pressures....

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mentioning

confidence: 99%

Very high growth rate chemical vapor deposition of single-crystal diamond

Yan

Vohra

Mao

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

235

109

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“…The quality of the film is dependent on the nature and the numbers of these defects. If one understands the nature of such defects and is able to control their numbers, one would be able to control the film quality and to use them as a source for coherent luminescence and other purposes.Cathodoluminescence (CL) [10,11], photoluminescence (PL) [2,6], positron-life time spectroscopy (PLS) [12] and electron-spin resonance (ESR) [13] methods are used for vacancy identification.The aim of this work is to show the possibility of making DLC films from liquid gas on metallic substrates and to obtain information about vacancies from UV-visible reflectance of DLC films.Carbon films were deposited on polished 2 × 3cm copper, steel and aluminium substrates from liquid gas (60% Butane and 40% Propane) by dc plasma technique. The substrate temperature was 200 • C and it was grounded.…”

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confidence: 99%

Diamond-like carbon film from liquid gas on metallic substrates

Vesaghi

Shafiekhani

1998

J. Phys. D: Appl. Phys.

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Liquid gas was used to produce DLC films on Cu, Al and steel substrates by DC plasma technique. The absorption in IR reflectance indicates, grown films are DLC. By deconvolution of room temperature UVvisible spectra of the films grown at 50 mtorr and 200 • C, in addition to the spectra lines reported for CL, PL, PLC and ESR, some new spectra lines were obtained. We also, have seen exciton absorption line at room temperature.PACS number: 71.35.C, 78.40, 81.05.T, 78.66, 61.72.J Typeset using REVT E X * e-mail address: vesaghi@physic.sharif.ac.ir † e-mail address: ashafie@theory.ipm. [9], were used to make DLC and a-C:H films. The gases which are used in most of these deposition methods are C 2 H 2 , CH 4 and C 2 H 6 pure or mixed with hydrogen. In all these techniques neutral or ionized atoms of carbon or various hydrocarbon precursor ions have been produced. These species with free (dangling) hand reach substrate, and those with sufficient time and energy stick to substrate and to each other.It is now well understood that films deposited by these techniques are amorphous or diamond-like carbon with no-long range order in structure. Because of the non-equilibrium nature of the growth, there must be some vacancies in these films [5]. These vacancies are produced by the impact of the ions reaching the growth surfaces with sufficient energy, sputtering off weak bonded species or damaging these surfaces. Also, there are vacancies in the domain-walls of the microcrystals. The vacancies at the surface of substrate with film are less important since the area of this surface is much smaller than total area of domain-walls. The quality of the film is dependent on the nature and the numbers of these defects. If one understands the nature of such defects and is able to control their numbers, one would be able to control the film quality and to use them as a source for coherent luminescence and other purposes.Cathodoluminescence (CL) [10,11], photoluminescence (PL) [2,6], positron-life time spectroscopy (PLS) [12] and electron-spin resonance (ESR) [13] methods are used for vacancy identification.The aim of this work is to show the possibility of making DLC films from liquid gas on metallic substrates and to obtain information about vacancies from UV-visible reflectance of DLC films.Carbon films were deposited on polished 2 × 3cm copper, steel and aluminium substrates from liquid gas (60% Butane and 40% Propane) by dc plasma technique. The substrate temperature was 200 • C and it was grounded. The chamber was flashed from 1 mtorr three times prior to deposition. The pressure and the gas flow were kept constant during deposition. Saturation voltage was applied to anode. Double beam Perkin-Elmer UV-visible spectrometer was used to measure the reflection and absorption of the films. The angle of incident beam was 6 • and measurements were done at room temperature. IR spectra was obtained at room temperature by Perkin-Elmer IR spectrometer. FIGURESFIG. 1. Room temperature IR spectra in a reflective mode for DLC film de...

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“…The spectrum of the photoionization cross-section of nitrogen can then be measured over more than three orders of magnitude, thus, nitrogen can be sensitively detected by CPM. Previous studies of substitutional nitrogen in CVD diamond [3,22] reported a wide range of values for the threshold energy of nitrogen donor (e.g. 1.5 eV in [3]), probably due to the above-described effect of hydrogenated surface or due to the nonlinearity of photocurrent spectra in a standard photocurrent measurement.…”

Section: Substitutional Nitrogenmentioning

confidence: 95%

On Photocurrent (and EPR) Study of Defect Levels in CVD Diamond

Rosa

Vaněček

Nesládek³

et al. 1999

phys. stat. sol. (a)

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Photocurrent spectroscopy is used for studying electronic defect states in the gap of optical‐quality CVD diamond. The constant photocurrent method (CPM), allowing to measure the optical (photoionization) cross‐section of defects, is applied on samples with a different surface treatment. The measured photoionization cross‐section spectra are discussed and attributed to main defects in CVD diamond layers. A photoionization cross‐section of a defect, with an onset at about 2.2 eV, is attributed to the single‐substitutional nitrogen defect (EPR P1 resonance at g = 2.0024). This defect is denoted as D2. Additionally, a defect with an onset at about 1.2 eV is observed on “as‐grown” samples or after additional hydrogen plasma treatment. This defect, denoted as D1, diminishes after oxidation of the diamond sample surface. The EPR g = 2.0028 resonance, which was also suggested to be H‐related, is studied as a function of hydrogenation and oxidation.

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Optical excitation of paramagnetic nitrogen in chemical vapor deposited diamond

Cited by 30 publications

References 0 publications

Very high growth rate chemical vapor deposition of single-crystal diamond

Very high growth rate chemical vapor deposition of single-crystal diamond

Diamond-like carbon film from liquid gas on metallic substrates

On Photocurrent (and EPR) Study of Defect Levels in CVD Diamond

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