Nanoporous ultrananocrystalline diamond membranes (original) (raw)
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JOM, 2012
Ultrananocrystalline diamond (UNCD) exhibits excellent biological and mechanical properties, which make it an appropriate choice for promoting epidermal cell migration on the surfaces of percutaneous implants. We deposited a $150 nm thick UNCD film on a microporous silicon nitride membrane using microwave plasma chemical vapor deposition. Scanning electron microscopy and Raman spectroscopy were used to examine the pore structure and chemical bonding of this material, respectively. Growth of human epidermal keratinocytes on UNCD-coated microporous silicon nitride membranes and uncoated microporous silicon nitride membranes was compared using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The results show that the UNCD coating did not significantly alter the viability of human epidermal keratinocytes, indicating potential use of this material for improving skin sealing around percutaneous implants.
Fabrication of thin diamond membranes by using hot implantation and ion-cut methods
Applied Physics Letters, 2017
A thin (2 lm) and relatively large area (3 Â 3 mm 2) diamond membrane was fabricated by cleaving a surface from a single crystal chemical vapor deposition (CVD) diamond wafer (3 Â 3 mm 2 Â 300 lm) using a hot implantation and ion-cut method. First, while maintaining the CVD diamond at 400 C, a damage zone was created at a depth of 2.3 lm underneath the surface by implanting 4 MeV carbon ions into the diamond in order to promote membrane cleavage (hot implantation). According to TEM data, hot implantation reduces the thickness of the implantation damage zone by about a factor of 10 when compared to implanting carbon ions with the CVD diamond at room temperature (RT). In order to recover crystallinity, the implanted sample was then annealed at 850 C. Next, 380 keV hydrogen ions were implanted into the sample to a depth of 2.3 lm below the surface with the CVD diamond at RT. After annealing at 850 C, the CVD diamond surface layer was cleaved at the damage-zone due to internal pressure from H 2 gas arising from the implanted hydrogen (ion-cut). A thin layer of graphite ($300 nm) on the cleavage surface, arising from the implanted carbon, was removed by O 2 annealing. This technique can potentially be used to produce much larger area membranes of variable thickness. Published by AIP Publishing.
Diamond and Related Materials, 2010
This review focuses on a status report on the science and technology of ultrananocrystalline diamond (UNCD) films developed and patented at Argonne National Laboratory. The UNCD material has been developed in thin film form and exhibit multifunctionalities applicable to a broad range of macro to nanoscale multifunctional devices. UNCD thin films are grown by microwave plasma chemical vapor deposition (MPCVD) or hot filament chemical vapor deposition (HFCVD) using new patented Ar-rich/CH 4 or H 2 /CH 4 plasma chemistries. UNCD films exhibit a unique nanostructure with 2-5 nm grain size (thus the trade name UNCD) and grain boundaries of 0.4-0.6 nm for plain films, and grain sizes of 7-10 nm and grain boundaries of 2-4 nm when grown with nitrogen introduced in the Ar-rich/CH 4 chemistry, to produce UNCD films incorporated with nitrogen, which exhibit electrical conductivity up to semi-metallic level. This review provides a status report on the synthesis of UNCD films via MPCVD and integration with dissimilar materials like oxides for piezoactuated MEMS/NEMS, metal films for contacts, and biological matter for a new generation of biomedical devices and biosensors. A broad range of applications from macro to nanoscale multifunctional devices is reviewed, such as coatings for mechanical pumps seals, field-emission cold cathodes, RF MEMS/NEMS resonators and switches for wireless communications and radar systems, NEMS devices, biomedical devices, biosensors, and UNCD as a platform for developmental biology, involving biological cells growth on the surface. Comparisons with nanocrystalline diamond films and technology are made when appropriate.
Fabrication of Ultrathin Single-Crystal Diamond Membranes
Advanced Materials, 2008
The extreme properties of diamond have led to its use in a wide variety of applications, from drilling for oil to ultrasharp knives for eye surgery. In the nanotechnology realm, diamond is being recognized as a material with great potential. For example, the extremely high Young's modulus suggests that diamond could be used in nano-electromechanical systems (NEMS) and quantum-NEMS applications, since diamond cantilevers will have higher oscillation frequencies than comparable cantilevers from other materials. Furthermore, diamond is chemically inert and biocompatible, and its surface can be functionalized, rendering it attractive for potential nano-bioapplications. There are many large dipole-moment color centers in the visible range that can act as artificial atoms for quantum optics. In particular, diamond-containing optically active color centers (especially the negatively charged nitrogen-vacancy NV À and nickelrelated NE8 centers) are rapidly emerging as ideal candidates for applications in quantum information processing (QIP). This promise is based on the proven NV À room-temperature single-spin coherence and readout properties of the ground states of NV À[5] and optical-spin polarization. The optical centers are also extremely bright and photostable, leading to applications as single-photon sources, for quantum-key distribution and metrology applications. There is thus a strong motivation for the development of new techniques to process diamond into complex functional structures. The present work reports significant advances in realizing such structures using ion-beam techniques, demonstrating the formation of buried single-crystal diamond membranes with thicknesses down to 210 nm suited for postprocessing and liftout.
Fabrication of free-standing diamond membranes
Thin Solid Films, 1996
We describe here a method for fabricating free.standing diamond membrane's. Diamond films were deposited on a silicon substrata by microwave plasma.assisted chemical vapor deposition and then part of the substrate chemically removed. The films described here were 15 mm in diameter with thickness of approximately 12 ,urn. A novel feature of oar approach lies in the method used to obtain the selective dissolution of the substrata; a container with O-rings ~,as used, instead of masks, allowing a fast and clean isotropie dissolution of pan of the silicon substrata. The deposited diamond films as well as the tree-standing membranes were characterized by scanning and transmission electron microscopy, electron diffraction and Roman spectroscopy, Eeywords: Diamond; Chemical vapour deposition; Plasma processing and deposition
Formation of nano-pores in nano-crystalline diamond films
Chemical Physics Letters, 2011
Various nano-pores in nano-crystalline diamond (NCD) thin films have been fabricated and characterized. Therefore in this work two aspects of NCD thin films synthesized by microwave assisted chemicalvapour-deposition (MWCVD) have been investigated. Firstly, the influence of CVD-growth conditions on the film morphology and chemical grain boundary composition and their impact on the mechanical properties. Second, the formation of nano-pores by selective etching of the non-diamond phase. Freestanding NCD membranes were fabricated and bulged to calculate the Young's modulus which can reach surprisingly high values (1100 GPa) close to single crystal diamond. The presence of nano-pores was verified by electrochemical experiments where ions have been used to detect the porosity.
Laser-Assisted Formation of High-Quality Polycrystalline Diamond Membranes
Journal of Russian Laser Research, 2020
A polycrystalline diamond film is grown on a 2 inch Si substrate using a microwave-plasma chemicalvapor-deposition technique. The high quality of the diamond films is confirmed by Raman spectra. A multiple-step procedure is used for local etching of the substrate to form the pattern of an array of 50 diamond membranes with the diameter in a range from 150 to 300 μm. The morphology of the membranes is examined using scanning electron microscopy. The membranes obtained can be used as the base material for the fabrication of pressure sensors, X-ray detectors and scintillators, and in quantum optics as optical resonators for single-color centers in diamond.
Study of porosity in permeable diamond membranes
Thin Solid Films, 1997
As reported previously, porous diamond membranes can be fabricated using a method based on growing diamond on a patterned silicon surface. Protrusions on the silicon surface act as molds for forming the pores on the diamond films. This method leads to a non-negligible pore size non-uniformity. The present work is concerned with identifying the process that accounts for this, so as to minimize its effects. The approach developed here is based on the digital processing of the scanning electron microscope (SEM) images obtained from selected pores in five different membranes. Published by Elsevier Science S.A.
Microstructural and biological properties of nanocrystalline diamond coatings
Diamond and Related Materials, 2006
In this study, the microstructural, mechanical, adhesion, and hemocompatibility properties of nanocrystalline diamond coatings were examined. Microwave plasma chemical vapor deposition (MPCVD) was used to deposit nanocrystalline diamond coatings on silicon (100) substrates. The coating surface consisted of faceted nodules, which exhibited a relatively wide size distribution and an average size of 60 nm. High-resolution transmission electron microscopy demonstrated that these crystals were made up of 2-4 nm rectangular crystallites. Raman spectroscopy and electron diffraction revealed that the coating contained both crystalline and amorphous phases. The microscratch adhesion study demonstrated good adhesion between the coating and the underlying substrate. Scanning electron microscopy and energy dispersive X-ray analysis revealed no crystal, fibrin, protein, or platelet aggregation on the surface of the platelet rich plasma-exposed nanocrystalline diamond coating. This study suggests that nanocrystalline diamond is a promising coating for use in cardiovascular medical devices.