Rozprawy doktorskie na temat „Nano-Crystalline Diamond”
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Wu, Tao. "Tooling performance in micro milling : modelling, simulation and experimental study". Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/7211.
Pełny tekst źródłaCai, Yixiao. "Bio-Nano Interactions : Synthesis, Functionalization and Characterization of Biomaterial Interfaces". Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277121.
Pełny tekst źródłaAbdolvand, Reza. "Thin-film piezoelectric-on-substrate resonators and narrowband filters". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28113.
Pełny tekst źródłaCommittee Chair: Farrokh Ayazi; Committee Member: James D. Meindl; Committee Member: John D. Cressler; Committee Member: Nazanin Bassiri-Gharb; Committee Member: Oliver Brand.
Chimowa, George. "Synthesis and characterization of nano-crystalline diamond films". Thesis, 2011. http://hdl.handle.net/10539/10410.
Pełny tekst źródłaThe objective of this project is to understand the details of the electronic transport in low dimensional carbon structures at low temperatures as well as high magnetic fields. The emphasis is on the quasi-2 dimensional thin grain boundary regions of nanodiamond films and one dimensional carbon nanotubes. As such nitrogen “doped” and undoped nanodiamond films were synthesized by the hot filament chemical vapor deposition method (HFCVD). The films were micro-structurally and electrically characterized using several techniques such as Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy and magnetoresistance (MR) measurements. The electronic transport properties were compared to the films deposited by microwave plasma enhanced chemical vapour deposition (MWCVD). The conductivity revealed a typical semiconducting and semi-metallic behavior for the HFCVD films depending on the nitrogen percentage in the chamber. The dephasing time of the electronic wave function was found to be weakly temperature dependant i.e. τ T-p with p < 1, a behavior reported in artificial superlattices. These results show potential application of these materials in novel nano-electronic devices. Previously the transport mechanism in nanodiamond films has been attributed to hopping conduction in the grain boundaries which is predominately disordered sp2 phases. Our studies on nanodiamond films have however shown different mechanisms in these films. We observed very little contribution from hopping and pronounced weak localization contributions in nanodiamond films. We thus establish the significance of tunneling transport in nanodiamond films. We also studied the electronic transport in films of metal filled multiwalled carbon nanotubes which show significant contribution from the hopping mechanism and a negative magnetoresistance at low fields that crosses over into positive MR at high magnetic fields.
Wu, Yao-Ming, i 吳耀明. "The study of arrayed nano-crystalline diamond devices". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/86720787459382320767.
Pełny tekst źródła國立臺灣科技大學
電子工程系
97
In this dissertation, the different array interval structure of nanocrystalline diamond (NCD) films were fabricated to study the effect on the field emission properties and gas ionization sensors on different pressure in nitrogen gas, respectively. NCD films were deposited on silicon substrate by microwave plasma chemical vapor deposition system. The surface morphology of NCD films were characterized by the field emission scanning electron microscopy. The characterization of NCD films were analyzed by Raman, XPS and AFM to show the quality, the surface composition and average roughness of nanocrystalline diamond, respectively. The array structures were fabricated by photolithography technique with the interval of 100 , 500 and 1000μm, respectively.. Field emission properties were measured with anode voltage from 0 to 1100 V. It is found that the turn on electric field were improved from 14.67 V/μm to 8.5 V/μm when the array structure interval was increased from 100μm to 1000μm. It is indicated that the field emission properties were improved with the array interval increased. The arrayed nano-crystalline diamond devices of gas ionization sensors were performed using N2 gas with the array interval of 100, 500 and 1000μm, respectively. However, it was found that the breakdown voltage decreased with the array interval decreased.
Chiang, Horng-Yi, i 江泓逸. "Influence on characteristics of “micro-crystalline diamond/ultra nano-crystalline diamond” in addition of argon gas". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/39425394058294825181.
Pełny tekst źródła國立臺灣師範大學
物理學系
99
Diamond films possess excellent physical, chemical, and mechanical properties, such that the syntheses of diamond films have been the focus of research. Moreover, the diamond films own marvelous field emission properties and have great patential for the application on the electron field emission devices. The chemical vapor deposition (CVD) has been the most widely utilized process for growing the diamond films. In this study, we used microwave plasma enhanced chemical vapor deposition (MPECVD) technique to synthesize microcrystalline diamond/ultrananocrystalline diamond (MCD/UNCD) composite films, for the purpose of investigating the growth mechanism and the related microstructural characteristics of the MCD/UNCD composite films. We first grow ultrananocrystalline diamond (UNCD) thin films as nucleation layers, followed by a secondary MPECVD process for growing microcrystalline diamond (MCD) thin films. We used Raman spectroscopy, field emission scanning electron microscopy (FESEM), optical emission spectroscopy (OES), and transmission electron microscopy (TEM) to characterize the MCD/UNCD thin films. The growth mechanism was discussed based on these investigations. In the first part of research, different proportion of argon (0-90 %) was added into CH4/H2 plasma for the deposition of the secondary MCD layer. Among them, the 50% Ar plasma results in the best electron field emission properties, that is, the turn-on field of 6.50 V/μm for (MCD50)1h/UNCD1h and of 5.0 V/μm for (MCD50)1h/UNCD3h films. TEM examinations indicated that the two step MPECVD process markedly modified the gannular structure of UNCD films, resulting in large-grain/small-grain duplex microstructure. In the second part of research, we changed the deposition time for growing the MCD layer (with 50% Ar plasma). We observe that 1 h deposition of MCD layer leads to the best electron field emission properties. The best electron field emission properties obtainable are:turn-on field of 5.0 V/μm with EFE current density of 0.70 mA/cm2 at an applied field of 27.5 V/μm.
鄭文秀. "Characteristic study and fabrication of field emitters by ultra-nano crystalline and micro-crystalline diamond". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/02184058059511767167.
Pełny tekst źródłaChen, Chien-Fu, i 陳建甫. "Carbon Embedded Nano-Crystalline Diamond Film and Its Field Emission Properties". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/17724384685705005960.
Pełny tekst źródła國立清華大學
材料科學工程學系
100
Diamond film has attracted immense attention as a field emission material due to its negative electron affinity and robust mechanical and chemical properties. It has been widely investigated. Based on literatures, the critical factors of diamond film field emission are grain size, the structure of grain boundary, conductivity, graphite structure distribution, structural defect density, surface roughness, surface functional groups, etc. In this work, nano-graphite fiber embedded nano-crystalline diamond films were synthesized, and it’s excellent electron field emission properties were studied. The nano-graphite fiber embedded nano-crystalline diamond film can be turned on at a low field as 4.4 V/μm and attain large field emission current density about 0.06 mA/cm2 at 7 V/μm applied field. The embedment of nano-graphite increased the conductivity of the film, and lowered the work function of nano-crystalline diamond film. The defects in the diamond structure created additional energy levels in the diamond band structure, which induced electron emission at low electric fields. The morphology and surface roughness of carbon embedded nano-crystalline diamond films were studied by field emission scanning electron microscope (FESEM) and AFM. Raman, XPS, XRD, TEM, CL are used to investigate the microstructure of the films. Conductivity and field emission properties were measured by four point probe and homemade field emission system respectively. In the future, the parameters of MPECVD grown nano-crystalline diamond film were further optimized to get better field emission cold cathode materials.
Wong, Xuan-Bo, i 翁瑄博. "Nano/Micro crystalline diamond on silicon-based templates for field emission studies". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/30469354544011056483.
Pełny tekst źródła國立臺灣科技大學
光電工程研究所
101
In this dissertation, Nano/Micro crystalline diamond were fabricated on different silicon-based structures to study the effect on the field emission properties. NCD and MCD were deposited on Planar-Si, Pyramid-Si and SiNWs/Pyramid-Si by microwave plasma chemical vapor deposition system. The surface morphologies of diamond were characterized by the field emission scanning electron microscopy. The characterizations of diamond were analyzed by Raman, XPS and AFM to show the quality, the sp3/sp2 ratio and average roughness of diamond, respectively. It is found that the turn on electric field of NCD/SiNWs/Pyramid-Si field emission cathode is lower (3.11 V/μm) through ultrasonication pretreatment than other structures such as NCD/Planar-Si (4.8 V/μm) and NCD/Pyramid-Si (4.35 V/μm). And the lower turn on electric field NCD/SiNWs/Pyramid-Si (3.2 V/μm) through rub and ultrasonication pretreatments than other structure such as NCD/Pyramid-Si (3.9 V/μm). While using C10H16 and ethylene glycol as seeds layer to deposite MCD on Planar-Si and Pyramid structures, the turn on field improved from 3.86 V/μm of MCD/Planar-Si to 3.15 V/μm of MCD/Pyramid-Si. And 4.5 V/μm of MCD/Planar-Si to 2.9 V/μm of MCD/Pyramid-Si by using C10H16 and diethylene glycol as seeds layer. Keyword: NCD, SiNWs, Pyramid
Ye, Ke-Yang, i 葉可揚. "X-ray Absorption Spectroscopy Study of Cu Ion Implanted Ultra-nano Crystalline Diamond Films". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/70538594278865464507.
Pełny tekst źródła淡江大學
物理學系碩士班
103
We have performed x-ray absorption near edge structure (XANES) study on Cu ion implanted, fluence varies from 1x1015 to 1x1017 ions/cm2, ultra-nano crystalline diamond (UNCD) films. From the XANES of C K-edge of the films, we found that the absorption intensity of sp3 structure decreased tremendously. In the meantime, the exciton peak and the second band gap are completely disappeared. We also observed the absorption intensities due to sp2 structure, C-OH bond, C-H bond and the surface defect peaks all increase. As the Cu-ion fluence reached 1x1016 ions/cm2, the absorption intensity of sp2 peak decreases, the intensities of C-H bond and the surface defect peaks increase. When the Cu-ion fluence reached 5x1016 ions/cm2, the sp2 peak shifts to lower energy, which may be related to the formation of amorphous carbon. Also the intensity of C-OH peak increases, and the intensities of C-H and the surface defect peaks decrease at fluence of 5x1016 ions/cm2. From the spectra of Cu K-edge, the intensity of the main peak, due to Cu 1s to 4p transition, decreases as the Cu-ion fluence increases. From Cu L2,3-edge we found an obvious broadening of the main absorption peaks at the highest fluence. When the fluence increases, sp3 structure decreases and sp2 structure increases. While the fluence exceeds 5x1016 ions/cm2, sp2 structure decreases and the amorphous carbon forms. At the highest fluence, Cu 3d-4s-4p hybridization increases.
Liu, Chun-Cheng, i 劉竣誠. "The development and application of the ultra-nano crystalline diamond film in field emission device". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/41702858328946360225.
Pełny tekst źródła國立清華大學
材料科學工程學系
95
In this work, the ultra-nano crystalline diamond film(UNCD) was grown on the molybdenum(Mo-Si)、tungsten(W-Si) films and molybdenum(Mo-B)、tungsten(W-B) bulks by microwave plasma enhanced chemical vapor deposition(MPECVD). The XRD and XPS analysis showed there is metallic carbide forming in the interface between diamond and metal films. In contrast, there is no metallic carbide forming between diamond and metal bulks. From SEM measurement, diamond deposited on the W-Si film was faster than on the Mo-Si film. The SEM also showed the grow rate in films are faster than bulks. Diamond film can be well patterned by dry etching of oxygen plasma. Using Al film be a mask, The diamond film can be pattern to produce 2-D lateral field emitter and 3-D field emitter. After hydrogen plasma treatment, the maximum current density can up to 3400 mA/cm2.XPS analysis also showed the surface of diamond was hydrogenated by hydrogen plasma. The other way to produce diamond film devices is selective area deposition(SAD). Taking Al and TiN as sacrificial layer, successfully pattern diamond by wet-etching process.
Bai, Shao-Huai, i 白少懷. "Reduced Graphene Oxide /N2 incorporated Ultra-Nano-Crystalline-Diamond on Nickel Foam for Pseudo-capacitors studies". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/286765.
Pełny tekst źródła國立臺灣科技大學
光電工程研究所
107
Abstract In this study, we used microwave systems to deposit ultra-nano diamonds on nickel foam substrates. In addition, we use reduced graphene oxide to increase the characteristics of pseudo-capacitors. This study is divided into two parts. The first part is mainly to discuss the quality of ultra-nanocrystalline diamond, which was grown by microwave plasma enhanced chemical vapor deposition (MPECVD) at different time durations. And also focused on the preparation of glucose derived reduced graphene oxide grown for different time durations at 200 ºC. We focus on the fabrication of pseudo-capacitor using nanosized diamond material with glucose derived reduced graphene oxide. The second part illustrates the oxygen plasma treatment on the surface ultra-nanocrystalline diamond, and in addition with the reduced graphene oxide solution. We explored the analysis of its pseudo-capacitance properties and analyzed the physical and electrical properties separately. According to the results, the nano-diamonds with different growth time have different grain size and film-forming properties by field emission scanning electron microscopy (FESEM). We used 1M NaOH aqueous solution as electrolyte, and it was observed that the 6-minute growth of the ultra-nanocrystalline diamond has a larger specific surface area than the structure after the film formation (i.e a film grown for 10 to 12 min). It possessed a highest specific capacitance of 163.3 F/g at a scan rate of 10 mV/s. Finally, we fabricate the materials using rGO-7.5hr/N-UNCD-6min for high performance pseudo-capacitors. It has a capacitance value 875 F/g at a scan rate of 10 mV/s, and also has good cycle stability with capacitance retention of 88% after 1000 cycles. It also exhibited an outstanding electrochemical stability, and can be one of the promising active materials in pseudo-capacitor applications.
Lin, Sheng-Chang, i 林聖昌. "Design of microwave plasma enhanced CVD system and their application in the growth of ultra-nano crystalline diamond film". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/44184002920054083112.
Pełny tekst źródła淡江大學
物理學系碩士班
98
A microwave plasma reactor was designed for growing large area diamond films by plasma-enhanced chemical vapor deposition process. The annular microwave coupling technique is adopted for designing the microwave plasma reactor. The first step in the reactor designing process is to determine the length (8 half-wavelength) of a rectangular wave guide with WR 340 cross-sectional dimension, bend it to form a annular resonance structure. The slots of proper dimension (2.5 mm x 50 mm) were located at the point of maximum surface current to couple the microwave from the annular resonator to the cylindrical quartz for the purpose of inducing the plasma. Deviation from the ideal resonance condition due to the introduction of plasma was simulated to assure that the sufficient coupling between the microwave and reaction gases. The mechanics of the setup based on the microwave simulation was designed and machined. The induction of air plasma was demonstrated to verify the correctness of the design. Moreover, ultra-nanocrystalline diamond films were successfully grown on Si-substrates using Ar/CH4 plasma in a setup of similar structure. It is found that the most important parameters for synthesizing UNCD films with good electron field emission properties are methane-content, total pressure and the microwave powers. The SEM microstructure changed most profoundly with these parameters, whereas the Raman structure is least sensitive to them. The EFE properties were optimized for the UNCD films grown in the following conditions: CH4=1%, microwave power of 1200 W and total pressure of 100 Torr.
Chang, Ming-Chen, i 張名辰. "A Study of Synthesis Large Area Nano Crystalline Diamond Films by Reciprocating Carrier System Using Single-Chip Microcomputer Controller". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/6k9v5x.
Pełny tekst źródła國立臺北科技大學
機電整合研究所
99
In this study, smooth and uniform large area nanodiamond thin film (NCD) were synthesized by using home-made microwave plasma jet chemical vapor deposition (MPJCVD) system with mechanical feed through. Linear motion reciprocating carrier, which used microcomputer single-chip to control the motor speeds, was added into MPJCVD system. The CNY70 photosensor was employed as a switch to change the different speeds which ensure uniform NCD films growth. Finally, the regional larger NCD film’s variations by reciprocating carrier system have been investigated. The ultrasonication pretreatment processes were used with nanodiamond powder mixture nanoametal powder solutions (Ti, Al) which aim to reduce the NCD films surface roughness. Both TiD and AlD pretreatment processes have significantly enhanced the formation of NCD films nuclei and lower surface roughness. From obtained results, lower reciprocating speed (48 rpm) was insured highest thickness. Moreover, through using various speeds for different areas could reduce the non-uniform large area NCD films thickness. The SEM results of as-grown large area NCD films revealed that highest uniform were attain at higher reciprocation speed (96 rpm) and 10 second of delay time.
Wu, Ying-Yu, i 吳盈佑. "Synthesis of Nano-crystalline diamonds with chlorinated wastes in supercritical fluids". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/67391397048100501870.
Pełny tekst źródła國立成功大學
環境工程學系碩博士班
93
CCl4 may cause catalytically depletion of ozone in the stratosphere. CCl4 may lead to kidney and liver damage, and is possibly carcinogenic to humans. Chlorine-containing wastes may be decomposed completely via high-temperature thermal oxidation. Undesirable by-products such as dioxins may be formed especially during cooling of the flue gases. Because of low dielectric constants, metal salts may possess low solubility of metal salts in SCFs (supercritical fluids). Chlorine in CCl4 may be abstracted by alkali cations due to formation of low solubility alkali salts in SCFs. As Cl in CCl4 is abstracted by alkali cations in SCFs, C atoms may be aggregated and form sp3 diamond carbons. The DFT calculations revealed that the alkali cations (Li+, Na+, and K+) may enhance the dissociation of C-Cl bonds of CCl4. The C2Cl6 intermediate may be yielded during formation of diamond. Experimentally, carbon, CO2 and NaCl were the main products in SC-CCl4 in the presence of Na2C2O4. A great quantity of DLCs and a small amount of diamond and graphite were found in the carbon products. The crystallite size of diamonds was about 1-2 nm. Disappearance of Na2C2O4 (87-100 %) were also found at 623-673 K for 12-24 hours. Nevertheless, a decrease of the sp3/sp2 ratios in carbon products was observed in Raman spectra. It seems that the sodium cations of Na2C2O4 may enhance the dissociation of C-Cl bonds in SC-CCl4 and form NaCl. Reconstruction on the surfaces of Na2C2O4 enables the reaction of Na2C2O4 with CCl4 to proceed. The growth of NCDs or DCLs may occur on the surface of Na2C2O4. In addition, different metal cations (Na+, K+ and Ca2+) were also proved to enhance the dissociation of C-Cl bonds in CCl4 and lead to the formation of metal halides. In addition, in the presence of catalysts such as iron or nickel powder, disappearance of Na2C2O4 (51-95 %) was enhanced at 573-673 K for one hour in SC-CCl4. The catalysts not only enhanced the dissociation of CCl4, but also reduce the activation energy for the formation of sp3 species of carbon. In supercritical water (SCW), at 673-773 K and 25-27 MPa for one hour, a large amount of DLCs and a small amount of diamond with 1-2 nm or graphite were observed in carbon products. Due to the low solubility of metal salts and low dielectric constants (1.7-2.8) in SCW at 673-773 K and 25-27 MPa, Na+ (Na2C2O4) in SCW may abstract Cl in CCl4 to form NaCl. Electron may transfer from oxalate to CCl4. Chlorine and high concentration of H2 may induce the aggregated C atoms to form diamond in SCW.