Electrical Properties of Thin Film and Bulk Diamond Treated in Hydrogen Plasma

1989 ◽  
Vol 162 ◽  
Author(s):  
Sacharia Albin ◽  
Linwood Watkins
Keyword(s):  
Natural Diamond ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Free Standing ◽  
Before And After ◽  
Type Ia ◽  
Bulk Diamond

ABSTRACTCurrent-voltage characteristics of type Ia synthetic diamond, type IIb natural diamond and free-standing diamond films were measured before and after hydrogenation. The diamond films were polycrystalline, deposited on sacrificial silicon substrates using a microwave chemical vapor deposition process. On hydrogenation, all the samples showed several orders of magnitude increase in conductivity. Hydrogenation was carried out under controlled conditions to study the changes in the I-V characteristics of the samples. The concentration of electrically active hydrogen was determined from the I-V data. Hydrogen passivation of deep traps in diamond is clearly demonstrated.

Infrared optical properties of CVD diamond films

1990 ◽  
Vol 5 (11) ◽  
pp. 2345-2350 ◽  
Author(s):  
X. H. Wang ◽  
L. Pilione ◽  
W. Zhu ◽  
W. Yarbrough ◽  
W. Drawl ◽  
...  
Keyword(s):  
Optical Properties ◽  
Microwave Plasma ◽  
Crystalline Silicon ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Optical Absorption Coefficient ◽  
Wave Number ◽  
Silicon Substrates ◽  
Free Standing ◽  
Infrared Optical Properties

Diamond films of 15–20 μm thicknesses were prepared by microwave plasma enhanced chemical vapor deposition onto crystalline silicon substrates. The growth surfaces of the films were rough with polycrystalline crystallographic habits, while the substrate sides of these films were smooth and featureless as viewed by optical microscopy. A heated cast iron scaife was used to polish the rough growth surfaces, and free-standing films were removed from the silicon substrates by dissolving the silicon in an aqueous HF. Both infrared optical transmission and reflection spectra were measured over the range of 600–4000 cm−1. For polished films, near 70% transmittance was obtained over the whole range, while the transmittance for nonpolished films was much lower and varied strongly with the wave number. Absorptions due to carbon-hydrogen stretching bands as well as a silicon carbide phase were observed in the transmission spectra. The optical absorption coefficient and the refractive index were found to vary from as high as 150 to as low as 7 cm−1 and 2.41 to 2.49, respectively (depending on the film quality and the wave number). A weak signature of the two-phonon absorption band of diamond was observed. The relationship between deposition conditions and infrared optical properties of diamond films before as well as after polishing is discussed.

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

1990 ◽  
Vol 5 (11) ◽  
pp. 2483-2489 ◽  
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.

Photoluminescence studies of polycrystalline diamond films

1990 ◽  
Vol 5 (11) ◽  
pp. 2502-2506 ◽  
Author(s):  
J. A. Freitas ◽  
J. E. Butler ◽  
U. Strom
Keyword(s):  
Strong Dependence ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Substrate Material ◽  
Nitrogen Vacancy ◽  
Free Standing ◽  
Zero Phonon Line ◽  
Phonon Line ◽  
Bulk Diamond

The photoluminescence spectra of polycrystalline diamond films prepared by filament assisted chemical vapor deposition are dominated by a defect band with a strong zero phonon line near 1.68 eV and weak phonon replicas at lower energies. The 1.68 eV line is blucshifted from the 1.675 eV zero phonon line associated with the neutral vacancy in bulk diamond. The line shape and position of the 1.68 eV line are shown to depend on substrate material (Si, Mo, Ni). The 1.68 eV emission for Ni and Mo substrates is interpreted in terms of the stress shifted and broadened neutral vacancy emission. The broader 1.68 eV line observed for Si substrates may indicate the additional effects of Si absorption by the diamond films. Films prepared by an oxygen-acetylene flame technique exhibit two additional luminescence bands with zero phonon lines at 1.95 and 2.16 eV. These lines have been tentatively assigned to nitrogen-vacancy complexes. The temperature dependence (6 K–300 K) of the luminescence of a free-standing diamond film, which had been deposited on a molybdenum substrate, is comparable to similar observations reported for bulk diamond. We have also observed a strong dependence of the PL spectra radially across a given combustion film and associated this with details of the flame chemistry.

Fabrication and electrochemical characterization of super-capacitor based on three-dimensional composite structure of graphene and a vertical array of carbon nanotubes

2018 ◽  
Vol 52 (22) ◽  
pp. 3039-3044 ◽  
Author(s):  
Daniel Choi ◽  
Eui-Hyeok Yang ◽  
Waqas Gill ◽  
Aaron Berndt ◽  
Jung-Rae Park ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Deposition ◽  
Composite Structure ◽  
Graphene Layer ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Vertical Array ◽  
Pressure Chemical

We have demonstrated a three-dimensional composite structure of graphene and carbon nanotubes as electrodes for super-capacitors. The goal of this study is to fabricate and test the vertically grown carbon nanotubes on the graphene layer acting as a spacer to avoid self-aggregation of the graphene layers while realizing high active surface area for high energy density, specific capacitance, and power density. A vertical array of carbon nanotubes on silicon substrates was grown by a low-pressure chemical vapor deposition process using anodized aluminum oxide nanoporous template fabricated on silicon substrates. Subsequently, a graphene layer was grown by another low-pressure chemical vapor deposition process on top of a vertical array of carbon nanotubes. The Raman spectra confirmed the successful growth of carbon nanotubes followed by the growth of high-quality graphene. The average measured capacitance of the three-dimensional composite structure of graphene-carbon nanotube was 780 µFcm−2 at 100 mVs−1.

The Control Of Intrinsic Stresses In Cvd Diamond Films With Multistep Processing

1995 ◽  
Vol 416 ◽  
Author(s):  
S. Nijhawan ◽  
S. M. Jankovsky ◽  
B. W. Sheldon
Keyword(s):  
Thermal Stresses ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Annealing Treatment ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Internal Stresses ◽  
Tensile Stresses ◽  
Si Substrates

ABSTRACTThe role of intrinsic stresses in diamond films is examined. The films were deposited on (100) Si substrates by microwave plasma-enhanced chemical vapor deposition. The total internal stresses (thermal and intrinsic) were measured at room temperature with the bending plate method. The thermal stresses are compressive and arise due to the mismatch in thermal expansion coefficient of film and substrate. The intinsic stresses were tensile and evolved during the deposition process. These stresses increased with increasing deposition time. A 12 hour intermediate annealing treatment was found to reduce the tensile stresses considerably. The annealing treatment is most effective when the diamond crystallites are undergoing impingement and coalescence. This is consistent with the theory that the maximum tensile stresses are associated with grain boundary energetics.

Residual stresses in chemical vapor deposition free-standing diamond films by X-ray diffraction analyses

2000 ◽  
Vol 288 (2) ◽  
pp. 217-222 ◽  
Author(s):  
O Durand ◽  
R Bisaro ◽  
C.J Brierley ◽  
P Galtier ◽  
G.R Kennedy ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Residual Stresses ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray

scholarly journals Doped Nanocrystalline Diamond Films as Reflective Layers for Fiber-Optic Sensors of Refractive Index of Liquids

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2124 ◽  
Author(s):  
Monika Kosowska ◽  
Daria Majchrowicz ◽  
Kamatchi J. Sankaran ◽  
Mateusz Ficek ◽  
Ken Haenen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Optic ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Fiber Optic Sensors ◽  
Nanocrystalline Diamond ◽  
Silicon Substrates ◽  
Boron Doped ◽  
Interferometric Sensor

This paper reports the application of doped nanocrystalline diamond (NCD) films—nitrogen-doped NCD and boron-doped NCD—as reflective surfaces in an interferometric sensor of refractive index dedicated to the measurements of liquids. The sensor is constructed as a Fabry–Pérot interferometer, working in the reflective mode. The diamond films were deposited on silicon substrates by a microwave plasma enhanced chemical vapor deposition system. The measurements of refractive indices of liquids were carried out in the range of 1.3 to 1.6. The results of initial investigations show that doped NCD films can be successfully used in fiber-optic sensors of refractive index providing linear work characteristics. Their application can prolong the lifespan of the measurement head and open the way to measure biomedical samples and aggressive chemicals.

Particle-Assisted Oriented Deposition of Diamond Thin Films

1996 ◽  
Vol 423 ◽  
Author(s):  
Dong-Gu Lee ◽  
Rajiv K. Singh
Keyword(s):  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
X Ray ◽  
Diamond Particles ◽  
Film Synthesis ◽  
Diamond Powders ◽  
Hot Filament

AbstractWe have developed a method for <111> oriented diamond film synthesis using micron-sized diamond particles. Different size of diamond powders were electrophoretically seeded on silicon substrates using diamond suspensions in organic solvents (acetone, methanol, and ethanol). Diamond suspension in acetone was found to be the best for obtaining uniform diamond seeding by electrophoresis. The thickness of diamond seeded films was changed by varying the applied voltage to observe the effect on the orientation of diamond particles. Then diamond films were deposited by the hot filament chemical vapor deposition (HFCVD) process. A preferred orientation with <111> direction normal to the substrate was obtained for monolayer coatings. The surface morphology, crystal orientation, and quality of diamond films were investigated using scanning electron microscopy, x-ray diffractometry, and Raman spectroscopy.

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