Ultrananocrystalline Diamond Films Research Articles

Tribological Properties of Ultrananocrystalline Diamond Films: Mechanochemical Transformation of Sliding Interfaces

Improving the tribological properties of materials in ambient and high vacuum tribo-conditions is useful for inter-atmospheric applications. Highly-hydrogenated and less-hydrogenated ultrananocrystalline diamond (UNCD) films with distinct microstructural characteristics were deposited on Ti–6Al–4 V alloy, by optimizing the plasma conditions in the chemical vapor deposition. Both the UNCD films showed less friction coefficient in ambient atmospheric tribo-contact conditions due to the passivation. This provides chemical stability to UNCD films under the tribo-mechanical stressed conditions which limits the transferlayer formation and conversion of UNCD phase into graphitization/amorphization. However, in the high vacuum tribo-conditions, highly-hydrogenated UNCD films showed low friction value which gradually increased to the higher magnitude at longer sliding cycles. The low friction coefficient was indicative of passivation provided by the hydrogen network intrinsically present in the UNCD films. It gradually desorbs and the dangling bonds are progressively activated in the contact regime, leading to a gradual increase in the friction value. In contrast, less-hydrogenated UNCD films do not exhibit low friction regime in high vacuum conditions due to the lack of internal passivation. In this case, the conversion of UNCD to amorphized carbon structure in the wear tracks and amorphous carbon (a-C) tribofilm formation on ball scars were observed.

Novel Biocompatible Ultrananocrystalline Diamond Coating Technology for a New Generation of Medical Implants, Devices, and Scaffolds for Developmental Biology

A new biomaterial paradigm for a new generation of implantable medical devices, prostheses, and scaffolds for stem cells growth and differentiation for developmental biology is provided by a novel multifunctional/biocompatible/body fluid corrosion-resistant ultra-nanocrystalline diamond (UNCD) film developed and patented in recent years. The UNCD coating provides a unique combination of multi functionalities, including biocompatibility, bioinertnes to chemical attack by body fluids, and surface chemistry, based on Carbon (C) atoms (element of life), to enable a new generation of implantable medical devices, prostheses, and scaffolds for tissue engineering, to impact the quality of life of people. This review article includes the following topics: 1) Brief description of the synthesis and properties of UNCD films and comparison with other diamond film technologies. 2) Brief description of key medical devices and prostheses under development, based on UNCD coatings. 3) Demonstration of UNCD as an outstanding scaffold for growing stem cells and induces differentiation for developmental biology, to treat specific medical conditions.Topics discussed include: • UNCD-coated microchip (artificial retina) is implantable on the eye’s retina to restore partial vision to people. Who are blind by retinitis pigmentosa, produced by genetically induced degeneration of the retina photoreceptors (The Argus II device, developed by a team of researchers and doctors from universities, national laboratories and the second Sight was currently implanted commercially in the USA and Europe,and it was selected by TIME magazine as one of the top 25 inventions for 2013). • UNCD- coated intraocular device for the treatment of glaucoma (intraocular pressure associated optical neuropathy that could lead to blindness). • UNCD-coated metal dental implants with order of magnitudelonger life and superior performance than current implants. • UNCD- coated prostheses (hips, knees and other metal-basedimplants); • New generation of Li-ion batteries (LIBs) for defibrillator/ pacemakers, with ≥ 10 × longer life and safer than current LIBs. • Description of UNCD-based scaffolds

Nanoscale investigation of enhanced electron field emission for silver ion implanted/post-annealed ultrananocrystalline diamond films

Silver (Ag) ions are implanted in ultrananocrystalline diamond (UNCD) films to enhance the electron field emission (EFE) properties, resulting in low turn-on field of 8.5 V/μm with high EFE current density of 6.2 mA/cm2 (at an applied field of 20.5 V/μm). Detailed nanoscale investigation by atomic force microscopy based peak force-controlled tunneling atomic force microscopy (PF-TUNA) and ultra-high vacuum scanning tunneling microscopy (STM) based current imaging tunneling spectroscopy (CITS) reveal that the UNCD grain boundaries are the preferred electron emission sites. The two scanning probe microscopic results supplement each other well. However, the PF-TUNA measurement is found to be better for explaining the local electron emission behavior than the STM-based CITS technique. The formation of Ag nanoparticles induced abundant sp2 nanographitic phases along the grain boundaries facilitate the easy transport of electrons and is believed to be a prime factor in enhancing the conductivity/EFE properties of UNCD films. The nanoscale understanding on the origin of electron emission sites in Ag-ion implanted/annealed UNCD films using the scanning probe microscopic techniques will certainly help in developing high-brightness electron sources for flat-panel displays applications.

Grain boundary dominated electrical conductivity in ultrananocrystalline diamond

N-type electrically conductive ultrananocrystalline diamond (UNCD) films were deposited using the hot filament chemical vapor deposition technique with a gas mixture of H2, CH4 and NH3. Depending on the deposition temperature and ammonia feed gas concentration, which serves as a nitrogen source, room temperature electrical conductivities in the order of 10−2 to 5 × 101 S/cm and activation energies in the meV range were achieved. In order to understand the origin of the enhanced electrical conductivity and clarify the role of ammonia addition to the process gas, a set of UNCD films was grown by systematically varying the ammonia gas phase concentration. These samples were analyzed with respect to their morphology and electrical properties as well as their carbon and nitrogen bonding environments. Temperature dependent electrical conductivity measurements (300–1200 K) show that the electrical conductivity of the samples increases with temperature. The near edge x-ray absorption fine structure measurements reveal that the electrical conductivity of the UNCD films does not correlate directly with ammonia addition, but depends on the total amount of sp2 bonded carbon in the deposited films.

High pressure Raman spectroscopic studies on ultrananocrystalline diamond thin films: Anharmonicity and thermal properties of the grain boundary

Ultrananocrystalline diamond (UNCD) thin film has been attracted widely to scientific community due to its attractive thermal and mechanical properties. Herein, we report the high-pressure behavior of grain boundary (GB) originated phonon modes and their correlation with thermal properties in UNCD film grown by microwave plasma enhanced chemical vapor deposition method. Spherical ultranano grains with size 3–4nm in these films were investigated by high-resolution transmission electron microscopy (HRTEM). Raman spectroscopic studies of UNCD with a pressure transmitting medium (up to 16GPa) and uniaxial pressure (up to 28GPa) revealed the presence of grain boundary phonons which are found to harden upon compression. GB phonons contribution to the specific heat of UNCD at room temperature is estimated to be 4.7314J/mol-K, which is ~80% of the reported theoretical molar specific heat Cv value (5.568J/mol-K). Using our experimentally obtained mode Grüneisen parameters, GB contribution to the thermal expansion coefficient of UNCD is estimated to be 0.5×10−6K−1. Grain boundaries of UNCD are found to be highly stable and Raman spectra showed reversible behavior upon release of pressure. Phonon spectra as a function of temperature down to 90K were used to obtain the anharmonicity of GB phonon modes. The first order temperature coefficient of trans-polyacetylene modes (ν1, ν2 and ν3) and E2g in-plane (G-band) modes of GB are obtained as −0.38×10−2, 1.69×10−2, −1.55×10−2 and −1.41×10−2cm−1K−1, respectively.

Locally Resolved Electron Emission Area and Unified View of Field Emission from Ultrananocrystalline Diamond Films.

In this paper, we study the effect of the actual, locally resolved, field emission area on electron emission characteristics of uniform planar conductive nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) field emitters. High resolution imaging experiments were carried out in a field emission microscope with a specialty imaging anode screen such that electron emission micrographs were taken concurrently with measurements of I-V characteristics. An automated image processing algorithm was applied to process the extensive imaging data sets and calculate the emission area per image. It was routinely found that field emission from as-grown planar (N)UNCD films was always confined to a counted number of discrete emitting centers across the surface, which varied in size and electron emissivity. It was established that the actual field emission area critically depends on the applied electric field and that the field emission area and overall electron emissivity improve with the sp2-fraction present in the film, irrespective of the original substrate roughness or morphology. Most importantly, when as-measured I-E characteristics were normalized by the electric field-dependent emission area, the resulting j-E curves demonstrated a strong kink and departed from the Fowler-Nordheim law, finally saturating at a value on the order of 100 mA/cm2. This value was nearly identical for all studied films regardless of substrate. It was concluded that the saturation value is specific to the intrinsic fundamental properties of (N)UNCD.

Tribofilm formation in ultrananocrystalline diamond film

Friction and wear properties of ultrananocrystalline diamond (UNCD) films are found to be superior, and therefore it could be useful for various applications. However, understanding of the tribological properties with respect to boundary phase composition in this material is not yet well understood. Here, the grain boundary phases such as graphite and amorphous carbon (a-C) of UNCD films were tailored during the chemical vapor deposition process by altering the Argon and Nitrogen gases in CH4 plasma medium. The significance of these grain boundary phases in UNCD film was discussed to explain the tribological properties. In run-in, friction coefficient was high in UNCDAr film deposited in CH4 (1%)/Ar plasma condition and it was decreased to lower value after longer sliding distance. However, ultrahigh wear resistance of this film was observed. Here, graphite and a-C phases were insignificant in the grain boundary region as evident from high resolution transmission electron microscope (HRTEM). Further, chemical bonding of these phases was quantitatively described by electron energy loss spectroscopy (EELS). In contrast, ultralow value of friction coefficient with significantly shorter run-in high friction regime was observed in UNCDN film deposited in CH4 (6%)/N2 plasma. Such a unique characteristic was described by the nanographite phase encasing the needle-like diamond grain of UNCDN film, forming core-shell granular structure. Atomic force microscopy (AFM) showed nucleation of two dimensional (2D) nanographite particles in the deformed wear track after run-in. This was possible due to the presence of core-shell granular structure in UNCDN film. Graphitic nature of the shell for needle-like diamond grains in the wear track was investigated by micro-Raman spectroscopy. Moreover, graphite and a-C tribofilm phase in the wear track was investigated by X-ray photoelectron spectroscopy (XPS) having spatial resolution micrometer scale. Needle-like diamond grains and graphite phase of tribofilm could be one of the primary reasons for the marked reduction in the friction coefficient.

Fundamentals towards large area synthesis of multifunctional Ultrananocrystalline diamond films via large area hot filament chemical vapor deposition bias enhanced nucleation/bias enhanced growth for fabrication of broad range of multifunctional devices

This paper describes studies to develop hot filament chemical vapor deposition (HFCVD)/Bias Enhance Nucleation-Bias Enhance Growth (BEN-BEG) process for nucleation/grow of relatively large area uniform multifunctional ultrananocrystalline diamond (UNCD) films on tungsten (W)-coated 100mm diameter silicon substrates, eliminating conventional wet diamond particles “seeding” of substrate surfaces. The HFCVD/BEN-BEG process generates a plasma, via electric field between positively bias filaments against negative substrates, producing positively charged and neutral Ar, CHx (x=1 2 3), C and H species and electrons in an Ar-rich/CH4/H2 gas mixture. The C+-based ions impacting the substrate surface nucleate a W-carbide layer, resulting in nucleation/growth of uniform UNCD films. The studies focused on understanding the HFCVD BEN-BEG mechanism for 0.5–2.5hrs. BEN, followed by no-bias 2.0hrs. growth of uniform UNCD films on 100mm diameter substrates. This approach eliminates the etching of UNCD films observed when doing BEG beyond 2.5hrs. of BEN, due to ion bombardment-induced sputtering and/or combined atomic hydrogen-induced chemical etching of the films. High Resolution Transmission Electron Microscopy showed formation of (001) and (101) oriented WC grains, inducing (111) diamond grains formations, turning into (220) and (311) orientation upon further growth. Large area HFCVD BEN-BEG process to grow multifunctional UNCD films may enable new generations of UNCD-based multifunctional devices.

Patterning of the surface termination of ultrananocrystalline diamond films for guided cell attachment and growth

The surface patterning of a biomaterial, i.e. placing areas with different surface chemistries next to each other is an important step for various biomedical and biotechnological applications, e.g. in biosensor technology, drug screening or tissue engineering. In the current work we investigated the patterning of the surface termination of ultrananocrystalline diamond (UNCD) films prepared by microwave plasma chemical vapor deposition. In order to achieve a high wettability contrast in the neighboring areas O- and F-terminations were selected. The sequence of the modifications and the feasibility of different masking techniques were tested in advance. Based on the achieved results the following process of surface patterning was applied. Initially the whole UNCD surface was modified by UV/O3 treatment rendering the surface O-terminated and strongly hydrophilic (contact angle against water of 11°). The partial masking of this surface before the second modification was achieved with a gold hard mask photolithographically structured and wet etched in form of a grid. After the second modification with CHF3 plasma which provided F-termination and hydrophobic character of the surface (contact angle>110°), the gold layer was removed. The results of the patterning of the surface termination were visualized by scanning electron microscopy revealing different contrasts of the areas with different terminations. Finally, human SH-SY5Y neuroblastoma cells were plated on the patterned UNCD surfaces and they exhibited preferential attachment and growth on the hydrophilic grid.

Growth of mirror-like ultra-nanocrystalline diamond (UNCD) films by a facile hybrid CVD approach**Development of CVD ultra-nanocrystalline diamond films and related high-precision machining products (International S&T Cooperation, No. S2015ZR1100).

In this study, growth of mirror-like ultra-nanocrystalline diamond (UNCD) films by a facile hybrid CVD approach was presented. The nucleation and deposition of UNCD films were conducted in microwave plasma CVD (MPCVD) and direct current glow discharge CVD (DC GD CVD) on silicon substrates, respectively. A very high nucleation density (about 1 × 1011 nuclei cm−2) was obtained after plasma pretreatment. Furthermore, large area mirror-like UNCD films of Φ 50 mm were synthesized by DC GD CVD. The thickness and grain size of the UNCD films are 24 μm and 7.1 nm, respectively. In addition, the deposition mechanism of the UNCD films was discussed.

The effect of Cu ion implantation and post-annealing on surface morphology and electron field emission in ultrananocrystalline diamond

Abstract The effects of 100 keV Cu ion implantation and subsequent annealing (i.e. common annealing or rapid annealing) at 500 °C on modifying the surface morphology and the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films were investigated. A Common annealing provides moderate enhancement in both electrical and EFE properties. Besides, the rapid annealing results in a low surface resistivity of 10.3 Ω/sq with a high mobility of 346.5 cm2 V−1 S−1for the UNCD film. The corresponding EFE behavior can be turned on at E0 = 5.3 V/μm, attaining a current density of 426.7 μA/cm2 at an applied field of 8.1 V/μm. The Mesh-like surface structures with the plate-like particulates, approximately 20–30 nm in size, distributed on the sample surface, which implies that the melting and recrystallization process have occurred due to the rapid annealing. Raman and X-ray photoelectron microscopy results demonstrated that the formation of Cu nanoparticles in UNCD films could catalytically provoke the formation of abundant nanographitic phase during rapid annealing process, forming the conduction channels for electron transport. Finally, the conducting and EFE properties of the UNCD films were remarkably improved.

On the integration of ultrananocrystalline diamond (UNCD) with CMOS chip

A low temperature deposition of high quality ultrananocrystalline diamond (UNCD) film onto a finished Si-based CMOS chip was performed to investigate the compatibility of the UNCD deposition process with CMOS devices for monolithic integration of MEMS on Si CMOS platform. DC and radio-frequency performances of the individual PMOS and NMOS devices on the CMOS chip before and after the UNCD deposition were characterized. Electrical characteristics of CMOS after deposition of the UNCD film remained within the acceptable ranges, namely showing small variations in threshold voltage Vth, transconductance gm, cut-off frequency fT and maximum oscillation frequency fmax. The results suggest that low temperature UNCD deposition is compatible with CMOS to realize monolithically integrated CMOS-driven MEMS/NEMS based on UNCD.

Microplasma device architectures with various diamond nanostructures

Diamond nanostructures (DNSs) were fabricated from three different morphological diamonds, microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films, using a reactive ion etching method. The plasma illumination (PI) behavior of microplasma devices using the DNSs and the diamond films as cathode were investigated. The Paschen curve approach revealed that the secondary electron emission coefficient (γ value) of diamond materials is similar irrespective of the microstructure (MCD, NCD, and UNCD) and geometry of the materials (DNSs and diamond films). The diamond materials show markedly larger γ-coefficient than conventional metallic cathode materials such as Mo that resulted in markedly better PI behavior for the corresponding microplasma devices. Moreover, the PI behavior, i.e. the voltage dependence of plasma current density (Jpl−V), plasma density (ne−V), and the robustness of the devices, varied markedly with the microstructure and geometry of the cathode materials that was closely correlated to the electron field emission (EFE) properties of the cathode materials. The UNCD nanopillars, possessing good EFE properties, resulted in superior PI behavior, whereas the MCD diamond films with insufficient EFE properties led to inferior PI behavior. Consequently, enhancement of plasma characteristics is the collective effects of EFE behavior and secondary electron emission characteristics of diamond-based cathode materials.

An insight of p-type to n-type conductivity conversion in oxygen ion-implanted ultrananocrystalline diamond films by impedance spectroscopy

The impedance spectroscopy measurements were used to investigate the separated contributions of diamond grains and grain boundaries (GBs), giving an insight into p-type to n-type conductivity conversion in O+-implanted ultrananocrystalline diamond (UNCD) films. It is found that both diamond grains and GBs promote the conductivity in O+-implanted UNCD films, in which GBs make at least half contribution. The p-type conductivity in O+-implanted samples is a result of H-terminated diamond grains, while n-type conductive samples are closely correlated with O-terminated O+-implanted diamond grains and GBs in the films. The results also suggest that low resistance of GBs is preferable to obtain high mobility n-type conductive UNCD films.

Structural properties of highly conductive ultra-nanocrystalline diamond films grown by hot-filament CVD

In this work we show the correlation of the electrical conductivity of ultra-nanocrystalline (UNCD) diamond films grown by hot filament chemical vapor deposition (HFCVD) with their structural properties. The substrate temperature, the methane to hydrogen ratio and the pressure are the main factor influencing the growth of conductive UNCD films, which extends from electrical resistive diamond films (<10-4 S/cm) to highly conductive diamond films with a specific conductivity of 300 S/cm. High-resolution-transmission-electron-microscopy (HRTEM) and electron-energy-loss-spectroscopy (EELS) have been done on the highly conductive diamond films, to show the origin of the high electrical conductivity. The HRTEM results show random oriented diamond grains and a large amount of nano-graphite between the diamond crystals. EELS investigations are confirming these results. Raman measurements are correlated with the specific conductivity, which shows structural changes of sp2 carbons bonds as function of conductivity. Hall experiments complete the results, which lead to a model of an electron mobility based conductivity, which is influenced by the structural properties of the grain boundary regions in the ultra-nanocrystalline diamond films.

Long term in vivo functional stability and encapsulation reliability of using ultra-nanocrystalline diamond as an insulating coating layer for implantable microchips.

Thin ultra-nanocrystalline diamond (UNCD) films were evaluated for their use as encapsulating coatings for long-term implantable microchips. The ex vivo hermetic properties of UNCD coatings of various thicknesses and their reaction with tissues in vivo were investigated. Leakage current tests showed that the ∼300 nm thick coatings grown on microchips in (1% H2) Ar/CH4 plasma for 2 hours rendered the surface electrochemically inactive, i.e., the microchips showed an extremely low leakage current density (1.3 × 10-4 A cm-2 at ±5 V). The tests simulate the human body environment ex vivo. Six months after the implantation of the chips in mice, the leakage current density of the thin O-UNCD-coated chips was approximately 7.76 × 10-5 A cm-2 at ±5 V, which is lower than that of chips with a UNCD coating of 1.53 μm thickness deposited for 12 hours (1.71 × 10-4 A cm-2 at ±5 V). These results indicate that the thin coatings can effectively protect the implant from degradation in vivo. Moreover, the relationship between the surface properties of the carbon-based implants and the foreign-body response they elicit was established. Our results strongly indicate that the formation of a fibrous capsule surrounding the implants depend on the surface features of the implants (i.e., roughness, surface area, surface energy, and amount of absorbed fibrinogen) and on the amount of cytokines or chemokines secreted by the host through acute and chronic foreign-body reactions. Finally, oxygen-terminated UNCDs are promising candidates for use as encapsulating coatings without any additional surface modification or functionalization. They exhibit good bioinertness and hermeticity, thus contributing to the direct long-term protection of implantable microelectronic devices from chemical attack by bodily fluids in a physiological environment.

Straight imaging and mechanism behind grain boundary electron emission in Pt-doped ultrananocrystalline diamond films

A detailed scanning tunneling microscopic (STM) investigation is carried out to directly image and understand the mechanism behind enhanced conductivity and electron field emission (EFE) properties for platinum (Pt) ion doped/post-annealed ultrananocrystalline diamond (UNCD) films. Straight imaging of conducting/non-conducting sites is mapped by dynamic scanning tunneling microscopy (D–STM). Energy dissipation mapping and the local current–voltage measurements illustrate that grain boundaries are the conducting/emitting sites. Further, this fact is supported by the high resolution current imaging tunneling spectroscopy (CITS). The formation of abundant conducting sp2 nanographitic phases along the diamond grain boundaries, confirmed from transmission electron microscopic examinations, is believed to be the genuine factor that helps for the easy transport of electrons and hence enhanced the conductivity/emission properties. The fabrication of these films with high conductivity and superior EFE properties is a direct and simple approach which opens up new prospects in flat panel displays and high brightness electron sources. Moreover, we expect the energy dissipation associated with assisted tunneling process of electrons from the tip of STM to sample surface, can be a very useful technique for imaging heterostructured semiconducting surfaces due to their electrical conductivity differences in nanometer scale, which can explain many physical and chemical properties.

Piezoresistivity of n-type conductive ultrananocrystalline diamond

Recent developments of a piezoresistive sensor prototype based on n-type conductive ultrananocrystalline diamond (UNCD) are presented. Samples were deposited using hot filament chemical vapor deposition (HFCVD) technique, with a gas mixture of H2, CH4 and NH3, and were structured using multiple photolithographic and etching processes. Under controlled deposition parameters, UNCD thin films with n-type electrical conductivity at room temperature (5×10−3–5×101S/cm) could be grown. Respective piezoresistive response of such films was analyzed and the gauge factor was evaluated in both transverse and longitudinal arrangements, also as a function of temperature from 25°C up to 300°C. Moreover, the gauge factor of piezoresistors with various sheet resistance values and test structure geometries was evaluated. The highest measured gauge factor was 9.54±0.32 at room temperature for a longitudinally arranged piezoresistor with a sheet resistance of about 30kΩ/square. This gauge factor is well comparable to that of p-type boron doped diamond; however, with a much better temperature independency at elevated temperatures compared to the boron-doped diamond and silicon. To our best knowledge, this is the first report on piezoresistive characteristics of n-type UNCD films.

Science and technology of diamond films grown on HfO2 interface layer for transformational technologies

This paper describes the science underlying the synthesis and characterization of microcrystalline diamond (MCD) to ultrananocrystalline diamond (UNCD) films on hafnium oxide (HfO2) thin films, grown on flat Si substrates and micro-pillars on Si substrates, for the first time. HfO2 is used as a novel inter-phase layer for the integration of microcrystalline (1–3μm grain size), nanocrystalline (10–200nm grain size), and ultrananocrystalline diamond (3–5nm grain size) as coatings on substrates used in transformational technologies such as silicon, oxides, and metals that need protective corrosion/mechanical abrasion resistant coatings developed in this work. Atomic layer deposition was used to grow HfO2 films with 5, 10, 30 and 100nm in thickness, while hot filament chemical vapor deposition was used to grow diamond films, respectively. High resolution transmission electron microscopy, X-ray photoelectron and Raman spectroscopies revealed the formation of an atomic scale hafnium carbide (HfC) interphase layer on the surface of the HfO2 film, which provides efficient nucleation for diamond film growth to produce tailored diamond surfaces on flat Si substrates and Si micro-pillars on flat Si substrates, for new transformational micro/nano-electronics and other high-tech technologies.

Low temperature hot filament chemical vapor deposition of Ultrananocrystalline Diamond films with tunable sheet resistance for electronic power devices

This paper describes the results from systematic experiments performed to investigate the influence of different substrate-filaments distances, surface-substrate temperatures and reaction of precursors during the growth of Ultrananocrystalline Diamond (UNCD) films via the hot filament chemical vapor deposition (HFCVD) process. The experimental results provide valuable information to understand the important role of key molecules (CHx, x=1, 2, 3) and atoms (H), resulting from the cracking of precursor molecules (CH4, H2) on the hot surface of the filaments, and the contribution of argon (Ar) inert gas atoms, all interacting on the surface of the substrates when using different filaments-substrate distances to produce films with different structures and properties. The interaction of the cracked molecular and atomic species at different filaments-substrate distances, play a critical role in the nucleation and growth of films with different structures, as observed by complementary analytical techniques. Films grown at 5, 15, and 30mm filaments-substrate distances exhibit graphite-disordered graphene phases, while those grown at 20mm distances exhibit mixed large UNCD-minor graphite mixed phases, and those grown at 25 and 35mm distances exhibit pure UNCD phase. UNCD films grown at ~600°C exhibit grain boundaries with sp2 and Trans-Polyacetylene (T-PA) dangling chemical bonds and low sheet resistance (~5Ω), while UNCD films grown at relativity low temperature (~490°C) exhibit high sheet resistance (~8MΩ) and more T-PA dangling bonds. The results presented in this paper indicate that UNCD and mixed UNCD/disordered graphene/graphite films can be grown with tailored resistivity enabling potential applications in electronic power devices.