Synthetic diamond electrodes: Photoelectrochemical behavior of vacuum-annealed undoped polycrystalline diamond films

Abstract The influence of diamond crystallinity and preferred orientation on electronic conductivity of synthetic diamond films grown by hot filament chemical vapor deposition (HFCVD) was investigated. The CVD diamond films of different morphologies and crystallite sizes varying from 36 nm to 67 nm, measured in h2 2 0i direction were considered. The charge transport mechanism in the diamond samples was studied using temperature dependent DC conductivity measurements. The obtained results showed that in the temperature range of 90 K to 300 K charge transport is realized via Variable Range Hopping (VRH, m = 1/4) mechanism. Using VRH model, the Mott parameters were evaluated i.e. density of states at Fermi level N(EF) (0.22 × 1015 eV-1·cm-3 to 1.7 × 1015 eV-1·cm-3), hopping energy W (43.5 meV to 142.3 meV) and average hopping distance R (1.49 × 10-5cm to 2.56 × 10-5cm). It was shown that above mentioned parameters strongly depend on diamond film preferential orientation.

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Oxidation of diamond films synthesized by hot filament assisted chemical vapor deposition

Journal of Materials Research ◽

10.1557/jmr.1990.2483 ◽

1990 ◽

Vol 5 (11) ◽

pp. 2483-2489 ◽

Cited By ~ 44

Author(s):

K. Tankala ◽

T. DebRoy ◽

M. Alam

Keyword(s):

Microwave Plasma ◽

Synthetic Diamond ◽

Natural Diamond ◽

Diamond Films ◽

Chemical Vapor ◽

Polycrystalline Diamond ◽

Low Oxygen ◽

Before And After ◽

Lower Temperature ◽

Hot Filament

Oxidation of polycrystalline diamond films on (111) Si wafers in air at temperatures up to 1073 K was investigated by thermogravimetry. The diamond films before and after partial oxidation were characterized by optical and scanning electron microscopy, x-ray, infrared, and Raman spectroscopy. The oxidation of synthetic diamond films started at a lower temperature than that for natural diamond. The rates of oxidation of the diamond films synthesized by the hot filament and the microwave plasma methods were intermediate between the rates of oxidation of the 111 and 100 planes of natural diamond crystals. The apparent activation energy for the oxidation of the synthetic diamond films agreed well with that for the oxidation of natural diamond via diamond to graphite transition at low oxygen pressures.

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Hybrid carbon-hydrocarbon structure

Perspektivnye Materialy ◽

10.30791/1028-978x-2021-9-79-84 ◽

2021 ◽

Vol 9 ◽

pp. 79-84

Author(s):

S. A. Eremin ◽

◽

N. O. Kudryashova ◽

I. A. Leontiev ◽

Y. M. Yashnov ◽

...

Keyword(s):

Synthetic Diamond ◽

Diamond Films ◽

Polycrystalline Diamond ◽

Average Diameter ◽

Diamond Powder ◽

Gas Mixture ◽

Nanocrystalline Graphite ◽

Diamond Powders ◽

Synthetic Diamond Powder ◽

Hybrid Carbon

A new hybrid carbon-hydrocarbon structure was discovered after pumping a gas mixture of methane and hydrogen through 314 – 400 µm synthetic diamond powder. The experiment was carried out on the microwave plasmachemical installation designed for deposition of polycrystalline diamond films. The main parameters during the experiment were the following: the power of the microwave generator 3,5 kW, the flow rate of hydrogen 400 ml/min, methane 20 ml/min, the pressure in the reactor chamber 63 torr. The gas mixture was pumped at pressure drop of 13 torr. The diamond powders were placed in molybdenum cups inserted into a copper pedestal. In the gaps between the diamond particles of the surface layer unidirectional thread-like structures (length 100 – 500 μm, diameter 2 μm) were found, some of which ended in spherical formations (average diameter 18 μm). Such a composition of thread-like structures and spherical formations was called “dandelion” one. Raman spectroscopy was performed to examine the nature of these formations. The thread-like structure was determined as monocrystalline graphite. The surface of the spherical formation was represented by spindle-shaped structures of nanocrystalline graphite (length 2 μm, thickness 200 nm) and nanodiamond grains with trans-polyacetylene chains [C2H2]n.

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Characterization of homoepitaxial diamond films by Electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088713 ◽

1991 ◽

Vol 49 ◽

pp. 880-881

Author(s):

D.P. Malta ◽

S.A. Willard ◽

R.A. Rudder ◽

G.C. Hudson ◽

J.B. Posthill ◽

...

Keyword(s):

Electron Microscopy ◽

Surface Defects ◽

Substrate Surface ◽

Diamond Films ◽

Chemical Vapor ◽

Polycrystalline Diamond ◽

Large Degree ◽

Rf Plasma ◽

Semiconducting Diamond

Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. A major goal of current device-related diamond research is to achieve a high quality epitaxial film on an inexpensive, readily available, non-native substrate. One step in the process of achieving this goal is understanding the nucleation and growth processes of diamond films on diamond substrates. Electron microscopy has already proven invaluable for assessing polycrystalline diamond films grown on nonnative surfaces.The quality of the grown diamond film depends on several factors, one of which is the quality of the diamond substrate. Substrates commercially available today have often been found to have scratched surfaces resulting from the polishing process (Fig. 1a). Electron beam-induced current (EBIC) imaging shows that electrically active sub-surface defects can be present to a large degree (Fig. 1c). Growth of homoepitaxial diamond films by rf plasma-enhanced chemical vapor deposition (PECVD) has been found to planarize the scratched substrate surface (Fig. 1b).

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Polycrystalline Diamond Films and Single Crystal Diamonds Grown by Combustion Synthesis

CIRP Annals ◽

10.1016/s0007-8506(07)61125-1 ◽

1990 ◽

Vol 39 (1) ◽

pp. 585-588 ◽

Cited By ~ 2

Author(s):

R. Komanduri ◽

L.L. Fehrenbacher ◽

L.M. Hanssen ◽

A. Morrish ◽

K.A. Snail ◽

...

Keyword(s):

Single Crystal ◽

Combustion Synthesis ◽

Diamond Films ◽

Polycrystalline Diamond

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Low energy ion-induced damage of polycrystalline diamond films

Diamond and Related Materials ◽

10.1016/0925-9635(94)90245-3 ◽

1994 ◽

Vol 3 (4-6) ◽

pp. 663-671 ◽

Cited By ~ 10

Author(s):

J. Ullmann ◽

A. Weber ◽

B. Mainz ◽

J. Stiegler ◽

T. Schuhrke

Keyword(s):

Diamond Films ◽

Polycrystalline Diamond ◽

Low Energy

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Investigation on the Machining of Thick Diamond Films by EDM Together with Mechanical Polishing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.24-25.377 ◽

2007 ◽

Vol 24-25 ◽

pp. 377-382

Author(s):

Rong Fa Chen ◽

Dun Wen Zuo ◽

Yu Li Sun ◽

Wen Zhuang Lu ◽

D.S. Li ◽

...

Keyword(s):

Diamond Films ◽

Polycrystalline Diamond ◽

Mechanical Polishing ◽

Polishing Process ◽

Two Stage ◽

Efficient Manner ◽

Raman Scattering Spectroscopy ◽

Electro Discharge Machining ◽

Diamond Polishing ◽

Cost Efficient

Although research on various diamond polishing techniques has been carried for years, some issues still need to be examined in order to facilitate application on large areas in a cost-efficient manner. A compositive technique for machining efficiently thick diamond films prepared by DC plasma arc jet is reported in the present paper. A two-stage polishing was applied on thick polycrystalline diamond films, by employing first electro-discharge machining (EDM) for rough polishing and subsequently mechanical polishing for finishing operations. Experimental results obtained clearly indicate the applicability of the proposed two-stage technique for fabricating transparent diamond films that can be used for the production of X-ray windows. Appropriate etching with EDM is an effective pretreatment method for enhancing the efficiency of rough polishing process in mechanical polishing of thick diamond film. The machined surfaces of diamond films are studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman).

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YBa2Cu3O7 Thin Films on Polycrystalline Diamond Films with Buffer Layers

MRS Proceedings ◽

10.1557/proc-275-137 ◽

1992 ◽

Vol 275 ◽

Cited By ~ 1

Author(s):

G. Cui ◽

C. P. Beetz ◽

B. A. Lincoln ◽

P. S. Kirlin

Keyword(s):

Thin Films ◽

Diamond Films ◽

Rf Sputtering ◽

Polycrystalline Diamond ◽

Fast Response ◽

Buffer Layers ◽

Multichip Modules ◽

Ir Detectors ◽

Ybco Films ◽

First Time

ABSTRACTThe deposition of in-situ YBa2CU3O7-δ Superconducting films on polycrystalline diamond thin films has been demonstrated for the first time. Three different composite buffer layer systems have been explored for this purpose: (1) Diamond/Zr/YSZ/YBCO, (2) Diamond/Si3N4/YSZ/YBCO, and (3) Diamond/SiO2/YSZ/YBCO. The Zr was deposited by dc sputtering on the diamond films at 450 to 820 °C. The YSZ was deposited by reactive on-axis rf sputtering at 680 to 750 °C. The Si3N4 and SiO2 were also deposited by on-axis rf sputtering at 400 to 700 °C. YBCO films were grown on the buffer layers by off-axis rf sputtering at substrate temperatures between 690 °C and 750 °C. In all cases, the as-deposited YBCO films were superconducting above 77 K. This demonstration enables the fabrication of low heat capacity, fast response time bolometric IR detectors and paves the way for the use of HTSC on diamond for interconnect layers in multichip modules.

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