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1
Han, Sanggil. "Cu2O thin films for p-type metal oxide thin film transistors." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/285099.
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The rapid progress of n-type metal oxide thin film transistors (TFTs) has motivated research on p-type metal oxide TFTs in order to realise metal oxide-based CMOS circuits which enable low power consumption large-area electronics. Cuprous oxide (Cu2O) has previously been proposed as a suitable active layer for p-type metal oxide TFTs. The two most significant challenges for achieving good quality Cu2O TFTs are to overcome the low field-effect mobility and an unacceptably high off-state current that are a feature of devices that have been reported to date. This dissertation focuses on improving the carrier mobility, and identifying the main origins of the low field-effect mobility and high off-state current in Cu2O TFTs. This work has three major findings. The first major outcome is a demonstration that vacuum annealing can be used to improve the carrier mobility in Cu2O without phase conversion, such as oxidation (CuO) or oxide reduction (Cu). In order to allow an in-depth discussion on the main origins of the very low carrier mobility in as-deposited films and the mobility enhancement by annealing, a quantitative analysis of the relative dominance of the main conduction mechanisms (i.e. trap-limited and grain-boundary-limited conduction) is performed. This shows that the low carrier mobility of as-deposited Cu2O is due to significant grain-boundary-limited conduction. In contrast, after annealing, grain-boundary-limited conduction becomes insignificant due to a considerable reduction in the energy barrier height at grain boundaries, and therefore trap-limited conduction dominates. A further mobility improvement by an increase in annealing temperature is explained by a reduction in the effect of trap-limited conduction resulting from a decrease in tail state density. The second major outcome of this work is the observation that grain orientation ([111] or [100] direction) of sputter-deposited Cu2O can be varied by control of the incident ion-to-Cu flux ratio. Using this technique, a systematic investigation on the effect of grain orientation on carrier mobility in Cu2O thin films is presented, which shows that the [100] Cu2O grain orientation is more favourable for realising a high carrier mobility. In the third and final outcome of this thesis, the temperature dependence of the drain current as a function of gate voltage along with the C-V characteristics reveals that minority carriers (electrons) cause the high off-state current in Cu2O TFTs. In addition, it is observed that an abrupt lowering of the activation energy and pinning of the Fermi energy occur in the off-state, which is attributed to subgap states at 0.38 eV below the conduction band minimum. These findings provide readers with the understanding of the main origins of the low carrier mobility and high off-state current in Cu2O TFTs, and the future research direction for resolving these problems.
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Zella, Leo W. "Metal Ion Diusion in Thin Film Chalcogenides." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1467075804.
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Ren, Huilin. "Current Voltage Characteristics of a Semiconductor Metal Oxide Sensor." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/RenH2001.pdf.
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Pecunia, Vincenzo. "Solution-based polymeric/metal-oxide thin-film transistors and complementary circuits." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708401.
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Barnes, Jean-Paul L. P. Barnes. "TEM studies of thin film oxide/metal nanocomposites." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398136.
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Whyte, Alex. "Thin film studies of planar transition metal complexes." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7966.
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At present the field of molecular electronics - also known as molecular semiconductors, organic semiconductors, plastic electronics or organic electronics - is dominated by organic materials, both polymeric and molecular, with much less attention being focused on transition metal based complexes despite the advantages they can offer. Such advantages include tuneable frontier orbitals through the ligand/metal interaction and the ability to generate stable paramagnetic species. Devices containing radical materials are particularly interesting in order to examine the interplay between conduction and spin - an effect which is not yet properly understood but can give rise to exotic behaviour. A series of homoleptic, bis-ligand Ni(II) and Cu(II) complexes were prepared using three structurally related phenolic oxime ligands, 2-hydroxy-5-t-octylacetophenone oxime (t-OctsaoH), 2-hydroxy-5-n-propylacetophenone oxime (n-PrsaoH) and 2- hydroxyacetophenone oxime (HsaoH). The complexes were characterised by single-crystal X-ray diffraction, cyclic voltammetry, UV/Vis spectroscopy, field-effect-transistor measurements, DFT/TD-DFT calculations and in the case of the paramagnetic species, EPR and magnetic susceptibility. Variation of the substituent on the ligand from t-octyl to n-propyl to H enabled electronic isolation of the complexes in the crystal structures of M(t-OctsaoH)2, which contrasted with π-stacking interactions observed in the crystal packing of M(n-PrsaoH)2 and of M(HsaoH) (M = Ni, Cu). This was further evidenced by comparing the antiferromagnetic interactions observed in samples of Cu(n-PrsaoH)2 and Cu(HsaoH)2 with the ideal paramagnetic behaviour for Cu(t-OctsaoH)2 down to 1.8 K. Despite isostructural single crystal structures for M(n-PrsaoH)2, thin-film X-ray diffraction and SEM revealed different morphologies depending on the metal and the deposition method employed. However, the complexes of M(n-PrsaoH)2 and M(HsaoH) failed to demonstrate significant charge transport in an FET device despite displaying the ability to form π- stacking structures. A series of planar Ni(II), Cu(II) and Co(II) dibenzotetraaza[14]annulenes (dbtaa) and dinapthotetraaza[14]annulenes (dntaa) were synthesised and studied crystallographically, optically, electrochemically and magnetically. Thin films of each of these complexes have been prepared by vacuum deposition to evaluate the field-effect transistor (FET) performance as well as the morphology and crystallinity of the film formed. Single crystal data revealed that Ni(dbtaa) and Cu(dbtaa) are isomorphous to each other, with Co(dbtaa) displaying a different crystallographic packing. The electrochemistry and UV/Vis absorption studies indicate the materials are redox active and highly coloured, with molar extinction coefficients as large as 80,000 M-1cm-1 in the visible region. The paramagnetic Cu(II) and Co(II) complexes display weak 1-dimensional antiferromagnetic interactions and were fit to the Bonner-Fisher chain model. The data revealed that the Co(II) species possesses much stronger magnetic exchange interactions compared with the Cu(II) complex. Each of the materials formed polycrystalline films when vacuum deposited and all showed ptype field-effect transistor behaviour, with modest charge carrier mobilities in the range of 10-5 to 10-9 cm2 V-1 s-1 . SEM imaging of the substrates indicates that the central metal ion, and its sublimation temperature, has a crucial role in defining the morphology of the resulting film. Structurally related Cu(II) and Ni(II) dithiadiazoletetraaza[14]annulene (dttaa) macrocycles were synthesised and studied in the context of their thin film electrochemical, conducting and morphological properties. Both the Ni(II) and Cu(II) complexes were found to be volatile under reduced pressure, which allowed crystals of both materials to be grown and the single crystal structures solved. Interestingly, the crystal packing of these heterocyclic macrocycles varies depending on whether the central metal ion is Cu(II) or Ni(II), which is in contrast to the analogous dibenzotetrazaannulenes complexes. Soluble Ni(II) analogues containing benzoyl groups on the meso- positions of the macrocycle (dttaaBzOR) were also prepared and contrasted with the insoluble Ni(dttaa) complexes in terms of their solution optical and electrochemical properties. Thin film electrochemical studies of Cu(dttaa) and Ni(dttaa) showed chemically reversible oxidative processes but on scanning to reductive potentials the films disintegrated almost immediately as the bulky counter tetrabutylammonium cation entered the thin film. FET studies undertaken on polycrystalline films of both complexes, using various device configurations and surface treatments, failed to realise any gate effect. Thin film XRD measurements indicate that films of both complexes formed by vacuum deposition are crystalline and contain a mixture of molecular alignments, with molecules aligning “edge on” and “face down” to the substrate. SEM imaging failed to effectively resolve the morphology of the films implying the sizes of the crystallites are small, which may help to explain the lack of FET effect. A series of bis-ligand diimine Ni, Cu and Pd complexes have been synthesised from the ligand 4,5-bis(dodecyloxy)benzene-1,2-diamine (dbdaH2). The same ligand was also used to prepare a series of soluble Cu(II) and Ni(II) tetraaza[14]annulene macrocycles. All the bis-ligand diimine complexes were found to suffer from instability in air due to the ease at which the complexes are oxidised. The Ni complex, Ni(dbda)2, was found to display a NIR transition in the region of 971 to 1024 nm depending on the polarity of the solvent that the molecule is dissolved in. Solution electrochemistry studies of Ni(dbda)2 reaffirmed the facile nature of the first oxidative process, with the HOMO energy calculated at -4 eV by hybrid-DFT. This compound failed to yield semiconducting behaviour in an FET device despite the use of surface treatments aimed at promoting suitable molecular alignment across the conducting channel.
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Reichmuth, Andreas. "Alkali metal adsorption and ultra-thin film growth." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338308.
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Krishnan, Subramanian. "Thin film metal-insulator-metal tunnel junctions for millimeter wave detection." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002759.
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Borovikov, Valery. "Multi-scale simulations of thin-film metal epitaxial growth /." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1216928358.
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Rycroft, Ian M. "Electric, magnetic and optical properties of thin films, ultra thin films and multilayers." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318142.
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Kiani, Ahmed. "Analysis of metal oxide thin film transistors with high-k dielectrics and source/drain contact metals." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648586.
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Greenspan, Jonathan. "The fabrication and characterization of metal thin film bolometers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0023/MQ50612.pdf.
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Wang, Chao-Hsiung. "The growth of thin film epitaxial oxide-metal heterostructures." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368667.
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Borovikov, Valery V. "Multi-scale Simulations of Thin-Film Metal Epitaxial Growth." University of Toledo / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1216928358.
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Okazaki, Nobuharu. "Molecular rectification with identical metal electrodes at low temperatures." Thesis, University of Exeter, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251190.
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Kamada, Rui. "Copper(indium,gallium)selenide film formation from selenization of mixed metal/metal-selenide precursors." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 226 p, 2009. http://proquest.umi.com/pqdweb?did=1654501631&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Barstow, Sean J. "Use of photosensitive metal-organic precursors to deposit metal-oxides for thin-film capacitor applications." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180015/unrestricted/barstow%5Fsean%5Fj%5F200312%5Fphd.pdf.
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Yang, Seung-Yeul. "Complex metal oxide thin film growth by metalorganic chemical vapor deposition." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3350.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Material Science and Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Deo, N. "Chemical vapour deposition of thin film metal layers for magnetic applications." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411101.
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Kristofzski, John Gregory. "Ionization-structure relationships of thin film and gas phase group VI metal-metal quadruple-bonded complexes." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184384.
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Principles involving the electronic structure of group VI metal-metal multiple bonded complexes are examined in order to provide insights into the intramolecular and intermolecular interactions of these systems. Examination of chromium, molybdenum and tungsten tetracarboxylate thin films by ultraviolet photoelectron spectroscopy has provided the first experimental evidence for the location of the σ ionization in dimolybdenum tetracarboxylate quadruple bonded complexes. These compounds have significant intermolecular interactions as thin films which destabilizes ionization of the valence σ state, allowing it to be experimentally observed. This is supported by the observed destabilization of the σ ionization feature of the ditungsten analogue in going to the thin film. The Cr₂(O₂CCH₃)₄ comparison shows a destabilization of the leading predominantly metal ionizations consistent with the broad range of M-M bond lengths observed for Cr₂ complexes. The Group VI M₂(mhp)₄ and M₂(chp)₄ [mhp=6-methyl-2-oxo-pyridine and chp=6-chloro-2-oxo-pyridine] complexes are also examined. The geometric constraints imposed on the compounds by the ligand effectively block intermolecular interaction axial to the metal-metal bond in the solid state. Comparison of the two ligand spectra, Hmhp and Hchp, has provided a unique opportunity to assign ionizations previously attributed to the keto form of the Hmhp tautomers. The spectra of the complexes exhibit minimal relative shifting of ionization features in going to the thin films because of this constraint. A band previously believed to be due to spin orbit coupling is assigned to the σ ionization in the ditungsten complex. The overall ionization band profiles of the two series correlate well, metal by metal, with the expected shifting due to substitution of the more electronegative chlorine atoms for a methyl group. The synthesis and characterization of Mo₂(N-t-butyl-acetamide)₄, the first tetraamidodimetal compound without large rings with delocalized pi structure, is described. The single crystal X-ray structure is presented, revealing the novel (one of three examples) cis configuration of the MoN₂O₂ ligand set. The Mo-Mo bond length of 2.063 Å is one of the shortest seen to date. A preliminary gas phase He I valence spectrum is reported.
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Chow, Chi Mei. "Effects of surface modification on metal-phthalocyanines based organic thin film transistors." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1152.
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Zhang, Bo. "Improvement of metal induced crystallization process and novel post-annealing technologies /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?ECED%202008%20ZHANG.
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Tamjidi, Mohammad R. "Characteristics of N-channel accumulation mode thin film polysilicon mosfets. /." Full text open access at:, 1987. http://content.ohsu.edu/u?/etd,132.
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Al-Dabbagh, J. B. "Some properties of thin metal films in reacting and non-reacting substrates." Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234487.
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Volkmann, Christian. "Atomic layer deposition of metal and metal chalcogenide thin films and nanolaminate composites." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E3AE-5.
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Plassmeyer, Paul. "Metal-Oxide Thin Films Deposited from Aqueous Solutions: The Role of Cation/Water Interactions." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22295.
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Metal-oxide thin films are used in a wide variety of electronic devices. Although many techniques have been developed to deposit thin films of metal oxides, there is still a need for alternative cost- and energy-effective deposition methods. Deposition of metal oxide thin films from aqueous solutions of all-inorganic metal salts is a viable method that meets these needs. Although many aqueous-deposited metal-oxide thin films have been successfully incorporated into functioning devices, many of the mechanisms that occur as precursors transition to metal oxides are not well understood.
The work presented in this dissertation is primarily concerned with examining the processes that occur as metal oxide thin films form from spin-deposited aqueous precursor solutions with a particular focus on the role of H2O in these processes. Chapter I summarizes methods for thin film deposition, and describes the use of aqueous metal salt solutions as viable precursors for the deposition of metal oxide thin films. Chapter II investigates the precursor chemistry, film-formation processes and properties of LaAlO3 thin films deposited from aqueous precursors. This chapter also serves as general guide to the processes that occur as metal-oxide thin films form from spin-deposited aqueous precursors. Chapters III and IV focus on the effects of H2O(g) during spin-deposition of precursor thin films and during the annealing process in which precursors are converted to metal oxides, respectively. The presence of H2O(g) during spin-deposition has a striking effect on the thickness of the resulting thin films and also affects the elemental gradient and density profiles. During annealing, H2O(g) reduces the temperatures at which counterions are expelled and influences the metal-hydroxide framework formation and its condensation to a metal oxide. The data also indicate that H2O(g) enhances diffusion of gaseous byproducts from within the films. Chapter V focuses on precursor concentration and its impact on the thermal evolution of thin films. The processes involved in the conversion of precursors to metal oxide thin films occur at lower temperatures as precursor concentration decreases. Although this is likely in part due to thickness effects, concentration-dependent precursor speciation may also be involved in lowering the temperatures at which films densify.2019-02-17
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Innes, R. A. "Surface plasmon-polaritons and thermally-induced optical nonlinearities in liquid crystals." Thesis, University of Exeter, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380733.
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Attard, G. A. "The structure and reactivity of copper, silver and gold overlayers on W(100)." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382046.
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Min, Byoung Koun. "Scanning tunneling microscopic studies of SiO2 thin film supported metal nano-clusters." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/2737.
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This dissertation is focused on understanding heterogeneous metal catalysts supported on oxides using a model catalyst system of SiO2 thin film supported metal nano-clusters. The primary technique applied to this study is scanning tunneling microscopy (STM). The most important constituent of this model catalyst system is the SiO2 thin film, as it must be thin and homogeneous enough to apply electron or ion based surface science techniques as well as STM. Ultra-thin SiO2 films were successfully synthesized on a Mo(112) single crystal. The electronic and geometric structure of the SiO2 thin film was investigated by STM combined with LEED, Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). The relationship between defects on the SiO2 thin film and the nucleation and growth of metal nano-clusters was also investigated. By monitoring morphology changes during thermal annealing, it was found that the metal-support interaction is strongly dependent on the type of metal as well as on the defect density of the SiO2 thin film. Especially, it was found that oxygen vacancies and Si impurities play an important role in the formation of Pd-silicide. By substituting Ti atoms into the SiO2 thin film network, an atomically mixed TiO2-SiO2 thin film was synthesized. Furthermore, these Ti atoms play a role as heterogeneous defects, resulting in the creation of nucleation sites for Au nano-clusters. A marked increase in Au cluster density due to Ti defects was observed in STM. A TiO2-SiO2 thin film consisting of atomic Ti as well as TiOx islands was also synthesized by using higher amounts of Ti (17 %). More importantly, this oxide surface was found to have sinter resistant properties for Au nano-clusters, which are desirable in order to make highly active Au nano-clusters more stable under reaction conditions.
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Zaidi, Syed Zulfiqar Ali. "Electrical and optical properties of some metal/SiOâ†x thin film systems." Thesis, Brunel University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307488.
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Lü, Bo. "Dynamics of the Early Stages in Metal-on-Insulator Thin Film Deposition." Licentiate thesis, Linköpings universitet, Plasma och beläggningsfysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-112136.
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Thin films consist of nanoscale layers of material that are used in many technological applications to either functionalize a surface or serve as parts in miniaturized devices. The properties of a film are closely related to its microstructure, which in turn can be tuned during film preparation. Thin film growth involves a multitude of atomic-scale processes that cannot always be easily studied experimentally. Therefore, different types of computer simulations have been developed in order to test theoretical models of thin film growth in a highly controlled way. To be able to compare simulation and experimental results, the simulations must be able to model events on experimental time-scales, i.e. several seconds or minutes. This is achievable with the kinetic Monte Carlo method. In this work, kinetic Monte Carlo simulations are used to model the initial growth stages of metal films on insulating, amorphous substrates. This includes the processes of island nucleation, three-dimensional island growth and island coalescence. Both continuous and pulsed vapor fluxes are investigated as deposition sources, and relations between deposition parameters and film morphology are formulated. Specifically, the film thickness at what is known as the “elongation transition” is studied as a function of the temporal profile of the vapor flux, adatom diffusivity and the coalescence rate. Since the elongation transition occurs due to hindrance of coalescence completion, two separate scaling behaviors of the elongation transition film thickness are found: one where coalescence occurs frequently and one where coalescence occurs infrequently. In the latter case, known nucleation behaviors can be used favorably to control the morphology of thin films, as these behaviors are not erased by island coalescence. Experimental results of Ag growth on amorphous SiO2 that confirm the existence of these two “growth regimes” are also presented for both pulsed and continuous deposition by magnetron sputtering. Knowledge of how to avoid coalescence for different deposition conditions allows nucleation for metal-on-insulator material systems to be studied and relevant physical quantities to be determined in a way not previously possible. This work also aids understanding of the growth evolution of polycrystalline films, which in conjunction with advanced deposition techniques allows thin films to be tailored to specific applications.
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Shen, Yonglong. "Development of thin film photovoltaic cells based on low cost metal oxides." Thesis, University of Bolton, 2014. http://ubir.bolton.ac.uk/803/.
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The major market barriers to the use of photovoltaic solar cells are high cost and long payback time of conventional technologies, based largely on the silicon material. In order to overcome the environmental problem resulting from the consumption of fossil fuels, all western countries are required to impose heavy subsidies to encourage the use of solar cells in the reduction of carbon consumption; thereby making them highly unsustainable. Therefore, it is necessary to develop solar cells based on low-cost metal oxides with large natural resources. The objective of this program is to investigate the effects of doping on the structural, optical and electrical properties of low-cost metal oxides, such as doped ZnO and copper oxides (CuO and Cu4O3). These are synthesised via sputter deposition and thermal oxidation method in air. Al doped ZnO is an n-type direct semiconductor with a band gap of around 3.5eV. Its crystalline structure is wurtzite, which is deposited widely by the RF reactive magnetron sputtering technology. In my work, the Al doped ZnO thin films were deposited by sputter with metal and ceramic targets. On the one hand, the influence of RF power on the structural, electrical and optical properties of Al doped ZnO thin films were investigated when they were deposited with metal targets. Conversely, the influence of O2 flow rate on the structural, electrical and optical properties of Al doped ZnO thin films was examined when they were deposited with ceramic targets. CuO is a p-type indirect semiconductor with a narrow band gap of 1.0-1.4eV. Its crystalline structure is monoclinic crystal system. CuO nanowires (NWs) were fabricated by the thermal oxidation method in air. It was found that CuO NWs not only grows on Cu sheets, but also on the Si, FTO, Al doped ZnO and glass substrates. For the growth of CuO NWs, the expanding parameters should meet the following requirements: growing temperature: >390°C and growing duration: ≥6hrs. The peeling-off of the CuO NWs on Cu sheets resulted from the formation of Cu8O and Cu64O between the Cu sheets and Cu2O layer. The electrical properties of a single CuO NW were measured using a nano probe station. The contact behaviour between a CuO NW and metal electrodes (Au and W) was schottky. The electrical resistivity of a CuO NW depended on the diameter of the NW. The contact behaviour between CuO NWs on Cu sheets with silver paste top electrodes was schottky as well. A simple PV cell based on CuO NWs-PCBM p-n heterojunction was fabricated, and the short circuit current, open voltage and fill factor of the PV cell was also measured. It indicated that CuO NWs can be utilized to fabricate diodes and PV cells. Copper oxides thin films were deposited by RF reactive magnetron sputtering technology. The phase structure of copper oxides thin films depended on the sputtering parameters. When the thin film was deposited without a bias power, only CuO was detected in the copper oxide thin films. The electrical properties of CuO thin films depended on the O2 fraction during the sputter process. The current-voltage (I-V) characteristics of CuO thin films with Cu electrodes demonstrated that it was influenced by the O2 fraction during the sputter process. Moreover, Cu4O3 is a p-type indirect semiconductor with narrow band gap of 1.0-1.4eV and its crystalline structure is tetragonal crystal system. When the copper oxide thin films were deposited with a bias power, only Cu4O3 phase was detected. Its structural, optical and electrical properties were studied. The optical band gap of Cu4O3 thin film was 1.37eV. Hall properties of Cu4O3 thin films were 1020cm-3, 10-2cm2·V-1·s-1 and 10-1Ω·cm. The Cu4O3-Al Abstract III doped ZnO p-n heterojunction demonstrated excellent rectifying performance, indicating that Cu4O3 is a good candidate for fabricating diodes and PV cells. In addition, Cu4O3 thin films were annealed at different temperatures in air. Furthermore, I studied the influence of annealing temperature on the structural, optical and electrical properties of Cu4O3 thin films.
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Johnston, David A. "The use of metal evaporation in the design and manufacture of enzyme electrodes." Thesis, University of the West of Scotland, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323763.
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Liu, Xuejing. "GPU Enhanced Simulations of Glancing Angle Deposition of Metal Thin-Films." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1325704817.
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Chen, De Xiu, and 陳德修. "Fabrication of thin-film metal nanobridge." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/64521610277335987225.
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Yang, Kai-Yu, and 楊鎧輿. "Photoelectrochemical studies of metal oxide/metal sulfide heterostructure thin film." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/41951714700818111613.
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博士國立中央大學
化學工程與材料工程學系
105
In this research, we prepared ZnO/Cu-In-Zn-S and CIS/ITO p-n junction heterogeneous structure thin films by using sprayed deposition method. In the first part, we present a sprayed composite thin film, comprising Cu-In-Zn-S (CIZS) particles embedded in ZnO matrix for photoelectrochemical hydrogen production from water splitting. CIZS, a photoactive semiconductor was used as a photon absorber, whereas ZnO channels as the pathway for charge transfer. It was found that the distribution of the CIZS particles had a direct impact on the PEC activity. A more homogeneous dispersion of smaller CIZS particles (0.56 μm) within ZnO matrix exhibited a higher photocurrent density, and 3.27 μmol/ cm2 hydrogen evolution for 5 h. Electrochemical impedance spectroscopy (EIS) was employed to analyze the charge transfer mechanism of this composite thin film. In addition, ZnO coating on top of CIZS particles also served as the adhesion and protection layers. All the PEC experiments were performed in 0.5 M K2SO4 electrolyte. No sacrificial reagents were used. The composite electrode was stable under illumination: 75.67% of photo-activity remained after 1 h illumination at a bias of 0.2 V vs. SCE. In the second part, we changed the ratio of precursor solution to prepare the different type of Cu-In-S (CIS) thin film semiconductors by the same method. In addition, the CIS p-type thin film is combined with ITO of high and low work function to produce CIS/ITO p-n junction thin film semiconductor. The photocurrent density of CIS/ITO p-n junction thin film compare favorably with CIS p-type thin film, and the current density of the most efficient CIS/ITO p-n junction thin film is about twice as much as the CIS p-type thin film. Therefore, we discussed the reason by using different method in the follow-up PEC test. This study demonstrates a simple and low-cost spray preparation of composite thin film consisting of particles embedded in any semiconductor matrix, and easy to change the ratio of precursor solution to make various thin film semiconductors.
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Yeh, Jen-Hao, and 葉仁豪. "Nano-texture Metal Thin Film for Sensors Applications." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31039226050678273141.
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碩士國立清華大學
動力機械工程學系
100
This study, we present nanoporous anodic aluminum template transformation technique to fabricate novel sensor. Using this technique to design, analysis and fabricate novel pizeoresistance sensors. They are temperature sensor, strain sensor and bending curvature sensor. Now the day, the technology of Micro- Electro- Mechanical System (MEMS) is primary using the semiconductor manufacture technology to manufacture micro system on silicon substrate. These days, with scale is going down to nano scale structure, the facilities of traditional manufacture in nano structure are expensive and spend lots of time becoming the largest problem in manufactory nano devices. Therefore, in this paper, we integrate metal thin film deposited on np-AAO template formatting nano-texture structure on silicon substrate and flexible PET substrate to develop sensor of novel sensing characteristics. By using two step anodizing fabrication process and micro/nano fabrication process to improve the adhesion between flexible substrate and metal thin film. This study has been succeed developed novel type of pizeorsistane of pizeoresistance sensor. The novel temperature sensor, strain and bending curvature have been analyzed characteristic and simulation verified. In the future, it could be used for novel low temperature fabrication process for pizeoresistance sensors in the future.
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Qiu, Hung-Sheng, and 邱宏昇. "Design and Analysis of Metal Thin Film Ignition Chip." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/31256282417941670783.
Full textAbstract:
碩士國立臺灣大學
應用力學研究所
92
Micro Electromechanical Technology has made great progress，using the Process-skill to manufacture Electrical-Igniting-Chip to replace an old Exploding-Bridge-Wire，Electrical-Igniting-Chip has the advantage of lower firing energy、shorter ignition time、higher exploding temperature, etc. To switch an air bag of cars，to ignite bombs and rockets，to burn blunt master explosive，to ignite fuel to push ahead and is a kind of more reliable product. When it is an military use，it is set on an ignition device which has the ignition powder Zr in it ,and the Exploding Bridge Wire must pass the military standard of low firing energy test、low ignition time test、avoiding electrostatic discharge test and avoiding electromagnetic disturbing. In the manufacture of semiconductor process,use the process of yallow light、the process of thin film、the process of lift off to manufacture the Exploding Bridge Wire. And have successfully manufacture the golden Exploding Bridge Wire, the size of it is 30μm in wedth and 600μm in lenth. The single Exploding Bridge Wire is single or is parallel connection of two、three and four Exploding Bridge Wire,and each resistences is about 14Ω、7Ω、4.5Ω、3Ω. In the respect of firing energy and ignition time, this paper use the idea of mathematical method, use the formulas for Electrical Gurney Energy and Electrical Heat to analyse the ignition time、firing energy and exploding temperature of ten kind of metal of the every Exploding Bridge Wire size. Change the parameter of RCL discharge system to get the numerical solution, from the solution to find the material and size of low firing energy and high exploding temperature, and it is a reverse engineering. In the respect of avoiding electrostatic discharge causing the accident of ignition of Zr , use the Zenor diode of backward direction and RC discharge circuit , the discharged current of low voltage of capacitance doesn’t pass the RC element connected to ground terminal, and ignite the Exploding Bridge Wire. Thousands of electrostatic voltage break down the zenor diode of backward direction , and electrostatic voltage discharge in Exploding Bridge Wire in nano seconds to avoid electrostatic voltage igniting. We analyse the electrostatic voltage discharge in 1 sec by using the numerical method,to caculate the time constant of RC circuit. It shows that the time constant of RC circuit should be about 0.26 nano second to satisfy both conditions, the temperature of Exploding Bridge Wire is lower than the ignition temperature of the powder of Zr, which is 300℃, and the voltage of Exploding Bridge Wire is lower than the military standard of the safe electrostatic voltage .
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FANG, YI-KAI, and 方毅凱. "Study of Metal Nanograting on Thin-film Solar Cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/y72ujb.
Full textAbstract:
碩士國立高雄師範大學
電子工程學系
105
In this thesis we presented the simulation and analysis of one-dimensional metallic nanograting in association with thin-film amorphous silicon solar cell, and the simulation was processed on SILVACO TCAD program with finite difference time domain (FDTD) method. First, we simulated different depth and period of aluminum nanograting placed between active layer and backside aluminum reflector. We found out when the nanograting depth and period are at 50nm and 600nm respectively, the conversion efficiency increased to 9.03% in compared with the device without nanograting at 8.24%. Then, we simulated four different metal, which are gold, silver, copper and aluminum, and used as the foundation of metallic nanograting. We found out under same nanograting depth and period the aluminum based structure had better conversion efficiency in compared with other type of metals.
40
Qiu, Hong-Sheng, and 邱宏昇. "Design and Analysis of Metal Thin-Film Ignition Chip." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/78752354531946842337.
Full textAbstract:
碩士國立臺灣大學
應用力學研究所
92
Micro Electromechanical Technology has made great progress，using the Process-skill to manufacture Electrical-Igniting-Chip to replace an old Exploding-Bridge-Wire，Electrical-Igniting-Chip has the advantage of lower firing energy、shorter ignition time、higher exploding temperature, etc. To switch an air bag of cars，to ignite bombs and rockets，to burn blunt master explosive，to ignite fuel to push ahead and is a kind of more reliable product. When it is an military use，it is set on an ignition device which has the ignition powder Zr in it ,and the Exploding Bridge Wire must pass the military standard of low firing energy test、low ignition time test、avoiding electrostatic discharge test and avoiding electromagnetic disturbing. In the manufacture of semiconductor process,use the process of yallow light、the process of thin film、the process of lift off to manufacture the Exploding Bridge Wire. And have successfully manufacture the golden Exploding Bridge Wire, the size of it is 30μm in wedth and 600μm in lenth. The single Exploding Bridge Wire is single or is parallel connection of two、three and four Exploding Bridge Wire,and each resistences is about 14Ω、7Ω、4.5Ω、3Ω. In the respect of firing energy and ignition time, this paper use the idea of mathematical method, use the formulas for Electrical Gurney Energy and Electrical Heat to analyse the ignition time、firing energy and exploding temperature of ten kind of metal of the every Exploding Bridge Wire size. Change the parameter of RCL discharge system to get the numerical solution, from the solution to find the material and size of low firing energy and high exploding temperature, and it is a reverse engineering. In the respect of avoiding electrostatic discharge causing the accident of ignition of Zr , use the Zenor diode of backward direction and RC discharge circuit , the discharged current of low voltage of capacitance doesn’t pass the RC element connected to ground terminal, and ignite the Exploding Bridge Wire. Thousands of electrostatic voltage break down the zenor diode of backward direction , and electrostatic voltage discharge in Exploding Bridge Wire in nano seconds to avoid electrostatic voltage igniting. We analyse the electrostatic voltage discharge in 1 sec by using the numerical method,to caculate the time constant of RC circuit. It shows that the time constant of RC circuit should be about 0.26 nano second to satisfy both conditions, the temperature of Exploding Bridge Wire is lower than the ignition temperature of the powder of Zr, which is 300℃, and the voltage of Exploding Bridge Wire is lower than the military standard of the safe electrostatic voltage .
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CAI, ZHENG-HONG, and 蔡政宏. "Analysis and measurement of metal thin-film thermal detector." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/38902861701552940442.
Full text
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林均翰. "Si thin film anodes modified by metal induced etching." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/32523835425293557361.
Full textAbstract:
碩士逢甲大學
材料科學與工程學系
104
In this study we investigate the electrochemical properties of a high capacity anode material, silicon (4200m Ah/g). Due the high theatrical capacity of silicon, only a smaller volume of active material is required for application in lithium ion batteries. However, silicon anode has one drawback that the material encounters serious cracking, which is attributed to the large volume expansion during the alloying and de-alloying process of Si toward lithium. During the process, stress accumulates and in several cycles silicon cracks and the broken parts loses electric contacts from the current collector. It results in significant capacity fading. This study proposes a method to address the problem using amorphous Si films prepared by physical vapor deposition. The deposited Si were futher modified by metal induced etching. The technique includes the electroless metal deposition (EMD) in conjunction with HF etching. The EMD-etching process fabricates Si nanowires (SNW) on single crystal Si wafers as well as amorphous Si thin films. It was found that the technique is able to suppress the irreversible electrochemical reactions, i.e. cracking of Si, and improve the cycling stability. The EMD-etching process can adjust the diameters and lengths of SNW to improve the cycling performances.
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LEE, CHENG-HUAN, and 李政圜. "12 Inches Metal Sputtering Equipment Thin Film Quality Improvement." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/968srw.
Full textAbstract:
碩士中華大學
機械工程學系
107
With the increasing investment in Taiwan and under the guiding of Mr. Morris Chang, the former CEO of Taiwan Semiconductor Manufacturing Company Limited (TSMC), TSMC has a market value of 6.7 trillion US dollars and becomes the world's top 100 companies in 2018. The technical capability of TSMC has reached the international leading level, even Intel Corporation (INTEL), which has long dominated the semiconductor manufacturing process, is looking forward to it. Therefore, semiconductors have developed into a mature industry in Taiwan now. Countries around the world constantly lure the talented persons of Taiwan to acquire the critical technology and look forward to gaining a foothold in Internet and Artificial Intelligence (AI) in the future. This paper researches that how does the 12-inch wafer metal sputtering equipment (PVD) improve the film thickness crystallization abnormality of AlTi film. First of all, we shall understand the factors affecting the film thickness and analyze problem through experimental methods to narrow down the scope. The survey can be divided into two main categories: process and hardware. The process includes process environment, temperature, pressure, gas, etc., and the hardware includes the component difference of reaction chamber, inch method, cavity leakage, etc. The key factors were found after the comparison and experimental verification. Finally, we solved the cause of the abnormal film thickness crystallization and achieved the product quality verification in accordance with the specifications of customer's production line after the improvement. Keywords: Semiconductor manufacturing process, Metal sputtering equipment (PVD), Film crystallization abnormality, Experimental methods, Helium detector, Build test, Residual Gas Analyzer (RGA).
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Yip, Gordon. "Development of Al2O3 Gate Dielectrics for Organic Thin-film Transistors." Thesis, 2008. http://hdl.handle.net/1807/11174.
Full textAbstract:
The focus of this thesis is on radio frequency magnetron sputtered aluminum oxide thin films developed for use as the gate dielectric for organic thin film transistors. The effect of top metal electrodes on the electrical characteristics of aluminum oxide metal-insulator-metal capacitors has been studied to determine an optimum material combination for minimizing the leakage current, while maximizing the breakdown field. The leakage current and breakdown characteristics were observed to have a strong dependence on the top electrode material. Devices with Al top electrodes exhibited significantly higher breakdown voltages compared to devices with Au, Ni, Cu and Ag electrodes. Introducing an Al diffusion barrier dramatically increased the breakdown field and reduced the leakage current for capacitors with Ag, Au and Cu top electrodes. The electrical characteristics were found to relate well to material properties, of the contacting metals, such as ionization potential and diffusion coefficient.
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Lyu, Rong-Jhe, and 呂榮哲. "Fabrication of Metal-Oxide Thin-Film Transistors and Inverters with “Film Profile Engineering”." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3kkm33.
Full textAbstract:
博士國立交通大學
電子工程學系 電子研究所
104
A new “film profile engineering” (FPE) scheme is conceived and established to fabricate sub-micron, high-performance metal-oxide thin film transistors (MO TFTs) and logic gates. In the scheme, a bridge is first constructed to suspend right over the gate electrode with an attempt to shadow the deposited species. Then, miscellaneous apparatuses with specific deposition conditions are employed to prepare the major thin films, i.e. gate dielectric, channel and source/drain (S/D) electrodes, with tailored and desirable film profiles to fabricate MO TFTs displaying superb performance. Two kinds of device structures are utilized to fabricate FPE MO TFTs with ZnO or InGaZnO4 (IGZO) channel. In one approach, sub-micron ZnO TFTs were fabricated with a one-mask process using Si substrate as the common gate. Excellent electrical characteristics in terms of high mobility (20 ~ 40 cm2/V.s), large on/off current ratio (ION/IOFF) (~ 109) and steep subthreshold swing (SS) (< 150 mV/dec) are demonstrated by the obtained devices. The other device structure is refined with a discrete metal gate. Although built with a more complex process, the scheme can effectively suppress the gate leakage current of the devices due to the considerably decreased gate-to-S/D overlap. The impact of the suspended bridge on the device characteristics of FPE TFTs is also probed. It is found that the elongation of the bridge dimension would facilitate the shadowing of the deposited species, resulting in the thinning of the underlying deposited films as well as a shift in the transfer curves of the MO TFTs to more positive position with improved SS. A problem arising from the early-manufactured, discrete-gate FPE ZnO TFTs is the low mobility < 10 cm2/V.s inferior to the common-gate ones. Further experiments are carried out to delve into the root cause of this degradation and find that the mobility degradation is due to the drastically increased S/D series resistance (RSD) resulted by the generation of unexpected TiN wires and disconnected S/D electrodes when the gate electrode is too protruding. Thinning of the gate electrode has been proved to be a viable way in addressing this issue. The FPE scheme is next modified to fabricate short-channel MO TFTs by making use of a laminated hardmask structure and alternate dry/wet etching steps. Based on the experimental results, the designed process shows much better capability in dimension control of the shadowing bridges than the previously developed photoresist trimming technique. Accordingly, sub-50nm ZnO TFTs involving a record-short 10 nm devices were successfully achieved. With proper control on the film thicknesses of gate dielectric and channel, the fabricated 50 and 30 nm ZnO TFTs display ION/IOFF higher than 107 and SS smaller than 200 mV/dec. Furthermore, despite the ultra-short channel, apparent switching behavior with ION/IOFF > 10 can still be exhibited by the devices with length of 17 and 10 nm. An innovative, three-dimensional (3D) IGZO inverter technology with vertically-stacked load and drive TFTs is finally proposed. Three patterned, stacked and separated TiN layers are built at first in this technology as the hardmask, load gate and drive gate, respectively. By utilization of the FPE scheme, the load TFT stacked on the drive one can be fabricated simultaneously. VTH of the two devices can be properly tuned through controlling the geometric parameters of the TiN layers. The 3D IGZO inverters fabricated with the new technology demonstrate excellent performance in voltage transfer characteristics (VTC) including full-swing switching, moderate noise margin, high voltage gain, good uniformity and superior immunity to light-induced instability.
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"Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.37039.
Full textAbstract:
abstract: A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors.
Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors.
Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs between low temperature and low stress (less than -70 MPa compressive) and device performance. Devices with a dark current of less than 1.0 pA/mm2 and a quantum efficiency of 68% have been demonstrated. Alternative processing techniques, such as pixelating the PIN diode and using organic photodiodes have also been explored for applications where extreme flexibility is desired.Dissertation/Thesis
Doctoral Dissertation Chemical Engineering 2016
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Chiao, Wen-Yu, and 焦文鈺. "3D FEM Simulation of Metal-polymer Bilayer Thin Film Nanoimprint." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/26786585567942851982.
Full textAbstract:
碩士國立中正大學
機械工程所
98
The polymer thin film layer is mainly used in nanoimprint process. It is uncommonly to apply imprint process to metal thin film due to its ultra-high stamp pressure and spring back problems. How to decide working temperature and metal layer structures to reduce the imprint force becomes the major research topics nowadays. In this thesis, we presented the relation with several parameters to reduce the imprinting force. The numerical mesh quality problems due to large deformation were improved by Coupled Eulerian-Lagrangian (CEL) analysis method. In addition, a FEM model of double-layer nanoimprint was built by verifying nanoimprint process (NIMB) experiment from references. Thereafter, simulations were performed to investigate the effects of the aluminum-to-polyimide thickness ratio and the substrate temperature on the imprint pressure required to obtain a complete filling of the mold cavities. The simulation results obtained for the variation of the imprint pressure with the aluminum thickness ratio, the polyimide thickness ratio, and the substrate temperature were compiled in the form of a contour chart, which provided a convenient means of establishing suitable processing conditions for a variety of nanoimprint applications. Finally, we also simulated the nanoimprint process of wire grid polarizer to predict the problems may occur.
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Yi-YinHo and 何怡瑩. "Application of metal silicide thin film to electrode of photodetectors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92573296750750005274.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
101
This thesis reported on the application of metal silicide thin film to electrode of photodectors. The relationship between the phase transitions and sheet resistance of metal silicide films, nickel silicide and ytterbium silicide, were discussed. The sheet resistance of metal silicide with poly silicon as a sacrificial layer was lower than amorphous silicon due to the grain size increasing. The SiNx film as a field insulator layer had lager compress stress than SiO2 film. The compress stress suppressed the phase transition of metal silicide thin films and improved the thermal stability, resulting a low sheet resistance. The device characteristics of the thin film transistors (TFT) photodetector with YbSi electrode was better than NiSi electrode owing to low Schottky barrier height. The lowest sheet resistance of NiSi and YbSi films were annealed by rapid thermal annealing at 500℃ and 600℃. Si nanocrystal embedded in the activeT Schottky barrier height. The lowest sh photocurrent (510nm) owing to quantum confinement effect and the surface state effect.
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Lin, Hsin-Ying, and 林欣穎. "Design and Analysis of Metal Oxide Thin-Film Transistor Circuits." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/77323052353789253517.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
99
Thin-film transistor (TFT) has been developed to be applied on the flat panel display (FPD) in decades. However, the low mobility and instability of a-Si:H TFTs and the poor uniformity of poly-Si TFTs are insufficient to applied on large size substrate and current driving circuits. The amorphous nature of amorphous oxide semiconductor (AOS) is attractive for manufacturing because of their high mobility (> 10 cm2/Vs), large-area, low-cost, transparent, and possibly flexible electronics applications. In this thesis, a high temperature deposited ZnO film is deposited to fabricate the high performance TFT, including an on-off ratio over 109. The effects of gate bias and thermal stress induced threshold voltage shift for ZnO TFTs are discussed. We compared three samples with various post ZnO growth annealing durations. The best result shows that the threshold voltage shift (ΔVth) is only 2.2V after a 1.3×104s stress at the gate bias 20V. And the ΔVth can be correlated to the stress time following the charge trapping mechanism. The characteristic trapping time τ was calculated to be 1.26×106 s. Finally, the characteristic trapping time was extracted at different temperatures and obtaining an average effective energy barrier Eτ of 0.57eV. The a-IGZO TFTs are employed to overcome the drawback of ZnO film forming defects and grain boundaries. The a-IGZO TFT reaches a higher saturation mobility of 16.5 cm2/Vs than ZnO TFT and has a better and more suitable performance than ZnO-based TFTs to develop the TFT circuits. The transconductance and extraction of resistivity in a-IGZO film by TLM method are also discussed. The design and implementation of the enhancement-mode inverter and the corresponding ring oscillator using a-IGZO TFTs are presented in the last part of this thesis. The DC gain and transient response are both extracted to examine the potential on realizing ring oscillators. An inverter DC gain of 2.5 biased at a supply voltage of 15V and a slew rate of 0.41V/μs are achieved separately. And an a-IGZO TFT ring oscillator with a channel length of 2μm and a beta ratio of 5 possesses an oscillator frequency 8.7 MHz and Vp-to-p = 0.37V biased at 20V. The operational frequency is expressed in a simple equation to further develop the frequency tuning method. It is mainly influenced by the channel length of the a-IGZO TFTs. Other design rules of thumb to improve the frequency are discussed. At last, the matching work by adding extra passive elements is required between circuit networks to minimize signal reflection at their interfaces. In summary, the device parameters can be sophisticated designed and optimized to improve the circuit performance.
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Tsai, Yun-Kuang, and 蔡昀光. "Study on the electrodeposition of metal-doped DLC thin film." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/62196587810684379533.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
99
Recently, synthesis of Diamond-Like Carbon (DLC) films has received considerable interest. Owing to their similar characteristics of diamonds, such as extreme hardness, chemical stability, and high heat conductivity etc, DLC films are regarded as one of the most promising materials. But the practical applications have been limited due to their high internal stress and insufficient adhesion at the interface between DLC film and substrate. Several methods used to the deposition of Me-DLC films have been proposed. Studies have shown that the internal stress was released and the adhesion also improved by doping metallic element into DLC films. Conventionally, metal incorporation in DLC films were prepared by vapor deposition. The requirement of high vacuum equipment makes the process complicated. Besides, there are many merits in electrodeposition, such as low cost, simplicity of experimental set up, and availability for deposition on complex shapes substrate in large area. In this study, electrodepositing technique was used to synthesize the amorphous Cu-DLC films deposited on ITO substrate, in which the pH value of electrolyte varied, to study the characteristics and the composition of DLC films. According to the I-t curves of deposition, the end of current density was used for the impedance comparison of films. With the addition of Cu, the resistance of the electron transportation in Cu-DLC was reduced, and the awl-shaped surface morphology was observed by AFM measurement, which could enhance the electron field emission properties of thin films. For Raman analysis, the effect of Cu addition would promote the sp2 bonding； this result corresponds with the increasing ID/IG value. It indicates that film becomes graphitization due to the addition of Cu and leads the shift of G-peak position toward lower wavenumber. ESCA spectra of C1s and Cu2p indicate no obvious evidence of Cu-C formation. The sp2/(sp2+sp3) ratio increases with the pH value. In addition, we found that Cu-DLC in acidic environmental condition, or doping as [Cu(NH3)n]2+ complex is more conducive to the growth of copper metal in DLC films, and has the lowest optical band gap value deduced by n&k analyzer. Finally, we discussed the thin film growth mechanisms and the characteristic of electron field emission for the applications in the future.