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1
Hu, Jingping. "Electronic Thin Film Materials." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491618.
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This thesis is concerned with investigations of the features of two types of electronic thin film materials: chemical vapour deposition (CVD) diamond and copper oxide based materials. CVD Diamond possesses excellent electrochemical properties. This thesis was concerned with investigating the fabrication and electrochemical properties of certain such diamond electrodes. The fabrication of diamond Ultramicroelectrodes (UMEs) was explored by coating tungsten needles with CVD diamond film under optimised. conditions, followed by selective insulation with different media. It was found that small grain diamond made the best electrode; large grain diamond coatings suffered from electrolyte leakage whereas nanodiamond had poor electrochemical properties. A range of tip insulation methods were examined, with most defined tips being produced by insulation with electrophoretic paint, followed by milling using Focused Ion Beam (FIB) methods. The utility of the tips prepared in this way in the SECM was demonstrated by imaging in biological media. The use of electrical conductive diamond as optically transparent electrode (OTE) opens novel applications for spectroelectrochemical studies due to the superior properties of diamond. The HFCVD diamond growth on fused silica quartz, ITO and AZO substrates was explored. The diamond membrane/ ITO structure was proposed and fabricated, exhibiting the best combination of optical transparency and electrical conductivity. Finally the changes in electrode properties as the diamond varied from macrocrystalline to nanocrystalline morphologies were studied. The second material investigated is copper oxide, specifically, cuprite (CU20) and SrCu202, a ternary Cu(I) oxide with a direct bandgap that arouses widespread interest as a p-type TCO. Their electronic structure and the nature of the hole charge carriers are topics of major current interest. The valence band and conduction band of both materials were studied by XPS in Daresbury, and XAS and XES measurements in ALS. The spectra are in good agreement with the PDOS from B3LYP calculations, showing strong hybridisation between Cu 3d and 0 2p states. Resonant Inelastic X-ray Scattering (RIXS) due to interband excitation close to Cu L3 edge threshold was first observed, conforming selection rule .6.L=O. This is the first observation of RIXS in close shell compound (dIO ). The UPS spectra of SrCu202 were measured with synchrotron radiation, and the changes in intensities of spectral features with varying photon energy were used to distinguish the contribution of 0 2p and Cu 3d states. Spectra showed that states at top of valance band are of dominant Cu 3d character and there is strong hybridisation between 0 2p and Cu 3d states which accounts for the hole mobility.
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Murphy, Craig E. "Pyroelectric thin film composite materials." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260162.
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Neeves, Matthew Kenneth. "Thin film electrochromic materials and devices." Thesis, University of the West of Scotland, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627902.
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This thesis investigates in detail the thin film materials required for the construction of a thin film electrochromic device, their production by vacuum deposition and other techniques, and their characterisation by SEM, XRD, and optical and electrochemical methods, leading to a greater understanding of the materials and considerations required in the design of electrochromic layers and devices constructed with said layers. Working devices consisting of electrochromes, electrolytes and transparent conducting electrodes are constructed by methods and upon a scale that are amenable to commercial-scale production. The hardware and software components of a unique real-time spectroscopic electrochemical characterisation cell are described, which have enabled the novel synchronous collection of wideband optical transmittance and electrochemical information at intervals as small as 20ms. Optimal process conditions for the production of electrochromic transition metal oxides of nickel, titanium, tungsten and the novel nickel-chromium oxide by advanced sputtering and electron-beam evaporation techniques are investigated and described in-depth. For comparison, devices are also constructed using the well-known electrochromic material iron hexacyanoferrate, or 'Prussian Blue'. It is essential for devices intended for eyewear applications that materials are eye-safe and that traffic light recognition is not unduly impaired. The electrochromic performance of individual materials and working devices is reported for all materials and spectroscopic data is used to calculate tristimulus co-ordinates and thus characterise the colour performance of the various materials and devices. Working devices also require transparent conductive electrodes. The transparent conductive oxide indium tin oxide (ITO), as prepared by two different sputtering methods is investigated. The sheet resistance of the ITO is shown to have a significant quantifiable effect upon the switching speed of working devices and this is reported in detail.
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Pearce, Alexander James. "Electromechanical properties of atomically thin materials." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15294.
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We discuss the effect of elastic deformations on the electronic properties of atomically thin materials, with a focus on bilayer graphene and MoS2 membranes. In these materials distortions of the lattice translate into fictitious gauge fields in the electronic Dirac Hamiltonian that are explicitly derived here for arbitrary elastic deformations, including in-plane as well as flexural (out-of-plane) distortions. We consider bilayer graphene, where a constant fictitious gauge field causes a dramatic reconstruction of the low energy trigonally warped electronic spectrum inducing topological transitions in the Fermi surface. We then present results of ballistic transport in trigonally warped bilayer graphene with and without strain, with particular focus on noise and the Fano factor. With the inclusion of trigonal warping the Fano factor at the Dirac point is still F = 1/3, but the range of energies which show pseudo diffusive transport increases by orders of magnitude compared to the results stemming out of a parabolic spectrum and the applied strain acts to increase this energy range further. We also consider arbitrary deformations of another two-dimensional membrane, MoS2. Distortions of this lattice also lead to a fictitious gauge field arising within the Dirac Hamiltonian, but with a distinct structure than seen in graphene. We present the full form of the fictitious gauge fields that arise in MoS2. Using the fictitious gauge fields we study the coupling between electronic and mechanical degrees of freedom, in particular the coupling between electrons and excited vibrational modes, or vibrons. To understand whether these effects may have a strong influence on electronic transport in MoS2 we calculate the dimensionless electron-vibron coupling constant for all vibron modes relevant for electronic transport. We find that electron-vibron coupling constant is highly sample specific and that the longitudinal stretching mode is the vibron with the dominant coupling. This however reaches maximum values which are lower than those observed in carbon nanostructures.
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Killian, Tyler Norton Rao S. M. "Numerical modeling of very thin dielectric materials." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Electrical_and_Computer_Engineering/Thesis/Killian_Tyler_16.pdf.
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Alexiou, I. "Hole transport materials for organic thin films." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595437.
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The aim of this project is to prepare and characterise novel triarylamine-based hole transport materials for xerographic applications that exhibit favourable electrochemical properties and amorphous nature. As an introduction, the six steps of the xerographic process and the common classes of hole transporting materials are described. The basic theories that have been developed for charge transport are discussed and an overview of the palladium-mediated amination and Suzuki reactions is given. In the following chapters, the synthesis and characterisation of a number of hole transporting triarylamines is reported. A series of linear trimeric arylamines is synthesised using the palladium-catalysed Suzuki protocol and their properties were determined using cyclic voltammetry, thermal gravimetric analysis and differential scanning calorimetry. Similar characterisation is carried out for a number of relatively unsubstituted phenyl and thiophene-based triarylamines. The synthesis of a series of oligomeric materials based on MPPD (Bis-methoxyphenyl-diphenyl-biphenyl-diamine) is reported and their electrochemical and thermal properties are investigated. Thiophene and dioctyl-fluorene-substituted MPPD-derivatives are studied as hole transport materials. Star-shaped and dendritic triarylamines with biphenyl and bithiophene-core molecules are also prepared using palladium-mediated chemistry and characterised. Finally, the attempts to synthesise macrocyclic triarylamine hole transporting materials are described in detail. The charge carrier properties for some of the synthesised materials are measured using the time-of-flight technique of using field-effect-transistors. Each set-up is described in detail and the hole mobility of the materials is calculated. A correlation between structural characteristics and charge-transporting properties is attempted.
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Baugher, Britton William Herbert. "Electronic transport in atomically thin layered materials." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91393.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2014.125
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 101-110).
Electronic transport in atomically thin layered materials has been a burgeoning field of study since the discovery of isolated single layer graphene in 2004. Graphene, a semi-metal, has a unique gapless Dirac-like band structure at low electronic energies, giving rise to novel physical phenomena and applications based on them. Graphene is also light, strong, transparent, highly conductive, and flexible, making it a promising candidate for next-generation electronics. Graphene's success has led to a rapid expansion of the world of 2D electronics, as researchers search for corollary materials that will also support stable, atomically thin, crystalline structures. The family of transition metal diclialcogenides represent some of the most exciting advances in that effort. Crucially, transition metal dichalcogenides add semiconducting elements to the world of 2D materials, enabling digital electronics and optoelectronics. Moreover, the single layer variants of these materials can posses a direct band gap, which greatly enhances their optical properties. This thesis is comprised of work performed on graphene and the dichalcogenides MoS 2 and WSe2. Initially, we expand on the family of exciting graphene devices with new work in the fabrication and characterization of suspended graphene nanoelectromnechanical resonators. Here we will demonstrate novel suspension techniques for graphene devices, the ion beam etching of nanoscale patterns into suspended graphene systems, and characterization studies of high frequency graphene nanoelectromechanical resonators that approach the GHz regime. We will then describe pioneering work on the characterization of atomically thin transition metal dichalcogenides and the development of electronics and optoelectronics based on those materials. We will describe the intrinsic electronic transport properties of high quality monolayer and bilayer MoS 2 , performing Hall measurements and demonstrating the temperature dependence of the material's resistivity, mobility, and contact resistance. And we will present data on optoelectronic devices based on electrically tunable p-n diodes in monolayer WSe2 , demonstrating a photodiode, solar cell, and light emitting diode.
by Britton William Herbert Baugher.
Ph. D.
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Kobese, Pakamisa. "Preparation and characterization of metal titanate materials." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53016.
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Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: Thin films and powders of Ni.Tiï), and CoxTi03 (where x = 0.005 - 0.9) with different stiochiometric ratios were prepared using sol gel techniques. These metal oxides were prepared by spin coating on silicon and titanium substrates followed, by annealing at 400°C and 800°C respectively under a temperature program. A range of films with MxTiOy (where x = 0.005 - 0.9) were prepared and then characterized by optical methods such as Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Rutherford Backscattering Spectroscopy (RBS). X-ray powder diffraction was also used to determine the structural properties of these metal oxides. XRD pattern peaks showed that the powder forms of these metal oxides were well crystallized. Thin films could be amorphous because strong peaks were not present. For nickel titanates preparation, the best trend is at the low concentration of Ni that is 0.3:1 Ni:Ti. It is pure with no impurities of NiO and Ti02. High concentration of Co ranging from 0.7-1:1 Co:Ti forms a C02Ti04 structure with cubic phase. The best route for the CoTi03 preparation is at the low cobalt concentration that is 0.5:1 Co:Ti. Scanning Electron Microscopy (SEM) shows that a film deposited on silicon or a titanium substrate is smooth, uniform and crack-free. It also shows that a cobalt titanate film deposited on a Si substrate is rough, with cracks, whereas on the Ti substrate, it is smooth, uniform and crack-free. AFM studies show that as the concentration of Ni:Ti is reduced and the roughness of the thin film is increased. SEM, FTIR, XRD and RBS suggest that the 0.3:1 and 0.5:1Ni:Ti films with 10nm and 11nm thickness, respectively, iii Stellenbosch University http://scholar.sun.ac.za iv have the same structure. RBS suggests that the 1:1 and 0.5:1 Co:Ti have C0I.39Ti02.29and CoTi04.2 structures with 13nm and 16nm respectively. XRD reveals that NiTi03 and CoTi03 have rhombohedral crystal structure.
AFRIKAANSE OPSOMMING: Dunlagies en poeiers van NixTi03 en CoxTi03 (waar x = 0.005 - 0.9) met verskillende stoigiometriese verhoudings was voorberei deur gebruik te maak van sol gel tegnieke. Hierdie metaaloksiedes was voorberei deur gebruik te maak van "spin coating" op substrate van silikon en titaan gevolg deur konstante verhitting by 'n 400°C en 800°C temperatuur program onderskeidelik. 'n Reeks van lagies met MxTiOy (waar x = 0.005 - 0.9) was voorberei en gekarakteriseer met optiese metodes soos Skandeer Elektron Mikroskopie (SEM), Atoom Interaksie Mikroskopie (AFM) en "Rutherford Backscattering Spectroscopy (RBS)." X-straal Poeier Diffraksie was ook gebruik om die strukturele eienskappe van hierdie metaaloksiedes te bepaal. XRD patroon pieke wys dat die poeier vorms van hierdie metaaloksiedes goed gekristalliseer was. Dunlagies mag ook amorf wees aangesien sterk pieke nie teenwoordig was nie. Vir nikkel titaniete is hierdie die algemene roete vir die NiTi03 voorbereiding. Die beste tendens is by lae konsentrasies van Ni naamlik 0.3:1 Ni:Ti. Dit is suiwer en het geen onsuiwerhede van NiO en Ti02 nie. Hoë konsentrasies van Co vanaf 0.7 - 1:1 Co:Ti vorm 'n Co2Ti04 struktuur met 'n kubiese fase. Die beste roete vir die CoTi03 voorbereiding is by lae kobalt konsentrasie naamlik 0.5 -1:1 Co:Ti. Skandeer Elektron Mikroskopie (SEM) wys dat 'n NiTi03 laag gedeponeer op silikon en titaan substrate gelyk was, eenvorming en sonder krake. Dit wys ook dat die kobalt titaan laag oppervlakte gedeponeer op 'n silikon substraat grof was en het krake getoon. Vir die Ti substraat het dit gewys dat die oppervlaktes gladwas, univormig en sonder krake. AFM studies wys dat as die konsentrasie Ni:Ti verminder word die grofheid van die dunlaag verminder. SEM, FTIR, XRD en RBS dui aan dat die 0.3:1 en 0.5:1 Ni:Ti dunlaag dieselfde struktuur het met 10nm en 11nm dikte onderskeidelik. RBS dui aan dat die 1:1 en 0.5:1 Co:Ti het C01.39Ti02.29en CoTi04.2 strukture onderskeidelik met 13nm en 16nm diktes. XRD toon aan dat NiTi03 en CoTi03 rhombohedrale kristal strukture het.
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Zhang, Xuefei. "Synthesis and Characterization of Zr1-xSixN Thin Film Materials." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/ZhangX2007.pdf.
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Milne, Stuart Brian. "Thin-film silicon based MEMS actuators and materials." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609898.
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Vedula, Ramakrishna. "Materials for High Temperature Thin Film Thermocouple Applications." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46493.
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The thermocouple systems used for the measurement of surface temperature in high temperature applications such as advanced aerospace propulsion systems and diesel engine systems are expected to perform in rapidly fluctuating and extremely high heat fluxes corresponding to high temperatures (in excess of 1400 K) and high speed flows. Traditionally, Pt/Pt-Rh based thin film thermocouples have been used for surface temperature measurements. However, recent studies indicated several problems associated with these thermocouples at temperatures exceeding 1000 K, some of which include poor adhesion to the substrate, rhodium oxidation and reaction with the substrate at high temperatures. Therefore, there is an impending demand for thermoelectric materials that can withstand severe environments in terms of temperature and heat fluxes.
In this study, thin films of titanium carbide and tantalum carbide as well as two families of conducting perovskite oxides viz., cobaltites and manganates (La(1-x)SrxCoO3, M(1-x)Cax MnO3 where, M=La,Y) were investigated for high temperature thin film thermocouple applications as alternate candidate materials. Thin films of the carbides were deposited by r.f. sputtering while the oxide thin films were deposited using pulsed laser ablation. Sapphire (1102) was used as substrate for all the thin film depositions. All the thin films were characterized for high temperature stability in terms of phase, microstructure and chemical composition using x-ray diffraction, atomic force microscopy and electron spectroscopy for chemical analysis respectively. Electrical conductivity and seebeck coefficients were measured in-situ using a custom made device.
It was observed that TiC/TaC thin film thermocouples were stable up to 1373 K in vacuum and yield high and fairly stable thermocouple output. The conducting oxides were tested in air and were found to be stable up to at least 1273 K. The manganates were stable up to 1373 K. It was observed that all the oxides studied crystallize in a single phase perovskite structure. This phase is stable up to annealing temperatures of 1373 K. The predominant electrical conduction mechanism was found to be small polaron hopping. Stable and fairly high electrical conductivities as well as seebeck coefficients accompanied with phase, structure, composition and microstructure stability indicate that these materials hold excellent promise for high temperature thin film thermocouple applications.Master of Science
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Hägglund, Fredrik. "Characterization of thin multi-layered materials using ultrasound /." Luleå : Department of Computer Science and Electrical Engineering, Luleå University of Technology, 2009. http://pure.ltu.se/ws/fbspretrieve/2985086.
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Qiu, Xiaofeng. "NANOSTRUCTURED MATERIALS FOR ENERGY CONVERSION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1207243913.
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Scabarozi, Theodore H. Jr Barsoum M. W. "Combinatorial investigation of nanolaminate ternary carbide thin films /." Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3189.
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Sklar, Zenon. "Quantitative acoustic microscopy of coated materials." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308851.
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Logan, Randy. "Optical metrology of thin films." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46094.
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Song, Ohsung. "Magnetoelastic coupling in thin films." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/28083.
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Scott, William Walter. "Micro/nanoscale differential wear and corrosion of multiphase materials /." Connect to this title online, 2001. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu994420446.
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Thesis (Ph. D.)--Ohio State University, 2001.Advisor: Bharat Bhushan, Dept. of Mechanical Engineering. Includes bibliographical references (leaves 145-152). Available online vai OhioLINK's ETD center.
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Sykesud, Christopher Geoffrey Dominic. "New organic materials for gas sensing by optical means." Thesis, Coventry University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282602.
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Parks, Carl L. "An experimental approach for studying the creep behavior of thin film/ substrate interfaces." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FParks.pdf.
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Anwar, M. "Spectroscopic investigations of amorphous complex dielectric materials." Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234036.
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Jiran, Eva. "Capillary instabilities in thin, solid films." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14000.
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Giermann, Amanda L. (Amanda Leah). "Templated dewetting of thin solid films." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52789.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 175-179).
The dewetting of solid metal polycrystalline films to form metal nanoparticles occurs by the nucleation and growth of holes in the film. For typical films on flat substrates, this process is not well-controlled and results in nanoparticles with nonuniform spatial and size distributions. Topographic substrates consisting of di-periodic inverted pyramid arrays and mono -periodic v-groove gratings of oxidized silicon were used to modulate the surface curvature of as-deposited polycrystalline gold films and control the dewetting process. The morphology of films dewetted on topographic substrates was found to depend on the both the relative geometry of the substrate and film thickness. Relatively thick films dewetted out of the pits and grooves prior to breaking up into particles while thinner films pinched off to form particles in the pits and grooves. If the pits or grooves were far apart, the pinch off also resulted in particles forming on the mesas between the pits. If the pits or grooves are close together, all the material pinches off into the topography. In the case of the inverted pyramids, this resulted in spatially ordered arrays of nanoparticles with narrow size distributions. A model that explains and predicts the effect of the relative geometry was developed based on competition between curvaturedriven evolution of the film-atmosphere interface and the dewetting of the film-substrate interface. It was also found that particles in both types of topographic substrates are strongly crystallographically oriented both out of the plane of the substrate and in the plane of the substrate despite the lack of an epitaxial relationship with the amorphous template.
(cont.) During the solid-state dewetting process, the growth of holes in the film is accompanied by material accumulation along the edge of the hole. Investigation of the dewetting edge at early stages revealed that the accumulation occurs unevenly in individual grains. Electron backscatter diffraction revealed that the unevenness is not due to grain orientation.
by Amanda L. Giermann.
Ph.D.
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Ariel, Nava. "Integrated thin film batteries on silicon." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33612.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.Includes bibliographical references (p. 147-158).
Monolithic integration has been implemented successfully in complementary metal oxide semiconductor (CMOS) technology and led to improved device performance, increased reliability, and overall cost reduction. The next element to be incorporated on the silicon chip is the power unit; possibly as part of the back end process of the very large scale integrated (VLSI) circuits' production. This thesis describes the work done in developing and studying thin film integrated lithium ion batteries compatible with microelectronics with respect to the material system employed, the cells' fabrication methods, and performance. The project consisted of three stages; first, a material system new to the battery application field was explored and power cells were fabricated and characterized. In the second stage, the fabrication process of the first material system cells was optimized thereby improving their performance. The third stage dealt with a more conventional battery material system, utilizing thin film technology to fabricate and explore power cells.
(cont.) All the cells fabricated in this work were created using microelectronic technology and were characterized by thin film analysis techniques and by measurement equipment commonly used for microelectronic device testing. The cells were fabricated in four sizes of active areas: 5x5 mm², 2x2 mm², lxl mm², and 0.5x0.5 mm². The first material system consisted of a novel lithium-free electrolyte in the form of an ultra-thin SiO₂ layer, thermally grown from sacrificial polysilicon layer on a doped polysilicon anode. The concept of SiO₂ as an electrolyte is innovative since common solid state lithium and lithium ion batteries consist of 1-2 ptm thick lithium-containing electrolytes. The controlled transport of lithium through SiO₂, 9-40 nm thick, was studied for electrolyte application. The fabricated LiCoO₂/SiO₂/polysilicon cells were successfully charged and discharged. This stage of the project demonstrated the concept of an ultra-thin lithium free electrolyte layer and introduces SiO₂ as an interesting candidate material. The second stage of the project focused on improving the LiCoO₂/SiO₂/polysilicon cell's performance and optimizing its fabrication process.
(cont.) Chemical mechanical polishing (CMP), a typical planarization method in microelectronics, new to the battery application field, was introduced in order to enhance the cell's properties and performance. LiCoO₂/SiO₂/polysilicon cells consisting of Si0₂ layers 7-40 nm thick were studied. Cells with the planarized polysilicon anode were characterized and the planarization effect was evaluated. This stage demonstrates the importance of interfacial quality in thin film batteries and the advantages incorporation of CMP as a planarization step in the fabrication process. Finally, the third stage of the project focused on applying the thin film technology knowledge and expertise to a more commonly used material system V₂0₅/LiPON/LiCoO₂. With the aim of reducing interfacial roughness, a surface morphology study of V₂0₅ was performed, tailoring different deposition conditions and surface morphology. Implementing the optimized conditions obtained from this analysis, a V₂0₅/LiPON/LiCoO₂ rocking-chair battery was studied next. The cells consisted of approximately 100 or 350 nm thick lithium phosphorus oxynitride (LiPON) electrolyte.
(cont.) This stage demonstrated the advantage of thin film technology in reducing film thickness and the performance enhancement achieved. The work described in this thesis approached the thin film battery subject from the microelectronic perspective, in order to "bring the battery into the clean room".
by Nava Ariel.
Ph.D.
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Agrawal, Parnika. "Magnetic thin films For spintronic memory." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115689.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 107-128).
Domain walls are regions of spatially non-uniform magnetizations in magnetic materials. They form the boundaries between two or more uniformly magnetized regions called domains. Skyrmions are circular magnetic domains with chiral domain walls that are interesting due to their stability and potential for fast motion. These spin structures can be used to encode Os and Is in spintronic memory. Chiral domain walls and skyrmions have been seen in magnetic thin films sandwiched between non-identical non-magnetic materials which have high spin-orbit coupling and Dzyaloshinskii-Moriya interaction. An optimization of the different physical interactions involved in magnetic thin films can result in stripe and labyrinth domain patterns which can then be transformed into skyrmion lattices. In this thesis, we present a detailed understanding of single- and multi-layer magnetic thin films along with all the relevant physical interactions. We show that inplane magnetic fields stabilize domain walls in thin films with Dzyaloshinskii-Moriya interaction. The application of in-plane magnetic fields is shown to create multi-domain patterns in films where the ground state is uniform magnetization. Next, we study the formation of stripe and labyrinth domain patterns in magnetic films. The domain widths obtained are compared with the predictions of several theoretical models developed over the last 50 years. The appropriate model that works for thin films with strong Dzyaloshinskii-Moriya interaction is identified with the help of micromagnetic simulations. The appropriate model includes effects of finite domain wall width and volume charges inside Neel domain walls. This model is then used to measure the Dzyaloshinskii-Moriya interaction in experimentally grown magnetic thin films. Thereafter, we highlight the role of other design variables such as the thickness of magnetic and non-magnetic layers, the choice of materials, and the role of geometrical confinement in controlling the length scale of the domain patterns. This work generates the necessary knowledge and develops techniques to engineer chiral spin textures in single- and multi-layer magnetic thin films.
by Parnika Agrawal.
Ph. D.
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Badir, Ashraf M. "Analysis of advanced thin-walled composite structures." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/12337.
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Gupta, Shailesh. "Mathematical Modeling of Thin Strip Casting Processes." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391679731.
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Pinitsoontorn, Supree. "3D atom probe studies of thin film magnetic materials." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492054.
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A combination of TEM and 3D atom probe has been used to study thin film magnetic materials for read head applications. Three different types of magnetic thin films have been investigated: (1) Co-based films for bias magnets, (2) magnetic tunnel junction (MTJ) with . AIOx barrier and (3) MTJ with MgO barrier. Unlike in longitudinal recording media, the Co-based films showed no Cr segregation to grain boundaries. This difference is likely to be due to the addition of Pt, which reduces the miscibility gap of the Co-Cr system, and film deposition at room temperature which reduces . the kinetics of segregation. However, some compositional variations were observed within grains. Increasing the angle of film deposition resulted in lower stress in the film, presumably due to better lattice matching between the magnetic layer and the seed layer. The observed coercivity enhancement with the larger deposition angle is attributed to changes in the resultant microstructure, specifically a smaller average grain size and more in-plane orientation of the magnetic easy axis. In the as-deposited MTJ. with an AIOx barrier, the barrier was found to be a discontinuous layer which was wavy and non-uniform in thickness. The AIOx layer was seen to form an interconnecting network of oxide islands, consistent with the islands forming at the grain boundaries of the underlayer. After annealing, the AIOx layer had become thicker, smoother, more uniform in thickness and contained fewer pinholes. The AI:O ratio changed from approximately 4:3 before annealing to close to the stoichiometry of 2:3 after annealing. Three energy contributions were considered as possible driving force for the transformation of the separated islands into a continuous layer: pinhole geometry, metal/oxide interface energy and strain energy. The improved TMR with annealing was mainly attributed to the improvement in the quality of the barrier. For the MTJ with an MgO barrier, the MgO deposited on a flat amorphous surface showed a [001] texture. The amorphous CoFeB partially crystallised after annealing and formed the (001)[110]CoFeB II (001)[100]MgO II (001)[110]CoFeB orientation relationship in some areas. Variations were observed in the chemistry of the barrier, but this was not as extreme as in the case of AIOx• The Mg:O ratio within the oxide was measured to be approximately 1:1 and was not changed after annealing. B was found to diffuse from the CoFeB layers: this must have occurred during deposition, as its distribution was the same before and after annealing. In the region of high MgO concentration, B was found mostly at the CoFeB/MgO interface and the CoFeB/Ru interface whereas in the region of low MgO concentration, B was found throughout layers. Mn in the AF layer was seen to have intermixed with the CoFe synthetic AF layer. The MgO layer topography was anti-correlated to the Ru layer but the effect decreased during annealing.
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Henry, John B. "Characterisation and screening of novel aromatic thin-film materials." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3782.
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The electropolymerisation of a range of indole derivatives results in the formation of redox active films. These redox films have been observed to be highly luminescent. Earlier studies have investigated electrochemical and photophysical properties, for potential applications such as fast response potentiometric sensors or novel materials for light emitting devices. The work in this thesis extends this approach to electrochemical and computational studies of a range of novel redox-active aromatic systems. This work has exploited the continuing increase of computing power, employing powerful quantum computational models to complement and augment electrochemical methods. Density Functional Theory has been used to show that prediction of oxidation potentials in good agreement with experimental values is achievable for a wide range of aromatic systems. Calculation of the electron spin density of the radical cations has also helped to elucidate the likely coupling locations for the formation of electroactive layers. It is observed that the nature of substituents and additional hetero groups to the aromatic systems can have a profound effect on electron spin density distributions. The redox-active species formed from indole dimers and 5-methylindolocarbazole have also been characterised. The species formed from electropolymerisation of 5- methylindolocarbazole has been found to be a mixture of three isomers of a 5- methylindolocarbazole dimer. Full characterisation of the product of the electropolymerisation of indole dimers was not possible; fluorescence work however suggests this to be a species with a greater degree of conjugation than either indole dimers or trimers. It is thought likely that this product is either a tetramer or longer chain polymer. This work demonstrates the applicability of a combination of computational and electrochemical methods to the characterisation of novel heteroaromatic systems.
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Kerman, Kian. "Ultra-thin solid oxide fuel cells: materials and devices." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11418.
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Solid oxide fuel cells are electrochemical energy conversion devices utilizing solid electrolytes transporting O2- that typically operate in the 800 - 1000 °C temperature range due to the large activation barrier for ionic transport. Reducing electrolyte thickness or increasing ionic conductivity can enable lower temperature operation for both stationary and portable applications. This thesis is focused on the fabrication of free standing ultrathin (<100 nm) oxide membranes of prototypical O2- conducting electrolytes, namely Y2O3-doped ZrO2 and Gd2O3-doped CeO2. Fabrication of such membranes requires an understanding of thin plate mechanics coupled with controllable thin film deposition processes. Integration of free standing membranes into proof-of-concept fuel cell devices necessitates ideal electrode assemblies as well as creative processing schemes to experimentally test devices in a high temperature dual environment chamber. We present a simple elastic model to determine stable buckling configurations for free standing oxide membranes. This guides the experimental methodology for Y2O3-doped ZrO2 film processing, which enables tunable internal stress in the films. Using these criteria, we fabricate robust Y2O3-doped ZrO2 membranes on Si and composite polymeric substrates by semiconductor and micro-machining processes, respectively. Fuel cell devices integrating these membranes with metallic electrodes are demonstrated to operate in the 300 - 500 °C range, exhibiting record performance at such temperatures. A model combining physical transport of electronic carriers in an insulating film and electrochemical aspects of transport is developed to determine the limits of performance enhancement expected via electrolyte thickness reduction. Free standing oxide heterostructures, i.e. electrolyte membrane and oxide electrodes, are demonstrated. Lastly, using Y2O3-doped ZrO2 and Gd2O3-doped CeO2, novel electrolyte fabrication schemes are explored to develop oxide alloys and nanoscale compositionally graded membranes that are thermomechanically robust and provide added interfacial functionality. The work in this thesis advances experimental state-of-the-art with respect to solid oxide fuel cell operation temperature, provides fundamental boundaries expected for ultrathin electrolytes, develops the ability to integrate highly dissimilar material (such as oxide-polymer) heterostructures, and introduces nanoscale compositionally graded electrolyte membranes that can lead to monolithic materials having multiple functionalities.Engineering and Applied Sciences
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Mastio, Emmanuel Antoine. "Materials engineering for high efficiency thin film electroluminescent devices." Thesis, Nottingham Trent University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302407.
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Peic, Antun. "Mesoporous thin-film materials studied by optical waveguide spectroscopy." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518293.
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A method was developed to access the interior of light-guiding structures in order to exploit the enhanced sensing potential of the highly confined electromagnetic field distributions, located within the core of a waveguide. The work presented in this thesis explores therefore the possibilities of optical waveguide spectroscopy utilising transparent mesoporous thin-film waveguides deposited on top of athin gold layer. These multi-layer assemblies are employed in a prism-coupling attenuated total internal reflection (ATR) configuration. The angular read-out of the reflected light intensity allows label-free detection schemes with high sensitivity to changes of the dielectric environment in the case of the presence of analyte molecules within the probing region. This optical waveguide spectroscopy technique has been used to study the real-timediffusion of Ruthenium 535-bisTBA (N-719) dye into mesoporous nanocrystalline titaniumdioxide films. The porous films were prepared on top of gold substrates and prism coupling was used to create a guided wave in the nanocrystalline film. Dying was carried out by bring the film into contact with a 3 x 10-4 moldm-3 dye solution and using optical waveguide spectroscopy to monitor the change in both the refractive index and theextinction coefficient of the nanoporous layer as dye diffused into the porous network. Dyeuptake in a 1.27 μm film was slow with the refractive index of the film still increasing after 22 hours.
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Abbas, Ali. "The microstructure of thin film cadmium telluride photovoltaic materials." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16389.
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In this work cadmium telluride thin film photovoltaic devices have successfully been produced using a novel closed-field magnetron sputtering technique. This technique offers the possibility of producing cells in an all-in-one vacuum process with the potential to provide a new lower cost production route. The sputtered cadmium telluride layers were characterised in detail using a range of advanced microscopy based techniques both in the as deposited and after the cadmium chloride treated state, a treatment that is necessary to produce a working cell. In the as deposited condition the cadmium telluride layer was seen to have a fine-grained columnar structure containing a high density of stacking faults. After the cadmium chloride treatment these grains recrystallized and the new grains were equiaxed with a much lower density of intragranular defects. Similar effects were also observed in samples prepared using close space sublimation. To understand this recrystallization behaviour during the cadmium chloride treatment, the key treatment parameters were systematically varied. Chemical analysis in Scanning Transmission Electron Microscopy (STEM) showed that chlorine travelled down the cadmium telluride grain boundaries and accumulated adjacent to the cadmium telluride/cadmium sulphide interface. This interface is where the cadmium telluride grains were found to recrystallise first during interrupted cadmium chloride treatments. The nature of the stacking faults was examined using High Resolution Transmission Electron Microscopy (HR-TEM). This showed that in localised regions up to one plane of atoms per sequence was missing based on the expected zinc blende structure. This changed the packing of the atoms such that a local change in crystal structure occurred. This local change in phase was successfully mapped using Electron Backscatter Diffraction in planar section produced using Focused Ion Beam milling. This was subsequently studied in more detail using Transmission Electron Backscatter Diffraction in the Scanning Electron Microscope, where the intra-granular arrangement of the phases was observed. HR-TEM was used to quantitatively measure the linear defects in the cadmium telluride layer after thermal annealing with and without the cadmium chloride present. This showed that annealing alone resulted in only a modest reduction in the density of linear defects and grain recrysallisation only occurred in the presence of cadmium chloride. Cadmium magnesium telluride (CMT) was successfully grown epitaxially onto the cadmium telluride as an electron reflector layer to improve cell performance. During deposition the cell experienced high temperatures and this caused the stacking faults to return in a cell that had been previously cadmium chloride treated. This resulted in a reduction in cell efficiency, providing another link between linear defects and a degradation in cell performance.
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Simpson, Robert E. "Chalcogenide thin film materials for next generation data storage." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/52041/.
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Data can be stored in the form of amorphous and crystalline marks within a chalcogenide thin film. Commonly Ge. Therefore Ga:La:S:Cu shows potential as a future electrical phase change data storage material.
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Hudson, David Christopher. "Two dimensional atomically thin materials and hybrid superconducting devices." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/16034.
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In this thesis a variety of topics concerning 2D materials that have been separated from bulk layered crystals are discussed. Throughout the thesis, single and few layers of graphene, fluorinated graphene, MoS2 and WS2 are used. Two new methods of freely suspending 2D materials are presented as well as a method of removing the background from optical images. This aids contrast measurements for the determination of the number of layers. Fluorinated graphene is found to be sensitive to beta radiation; the resistance of fluorinated graphene transistors is shown to decrease upon exposure to the radiation. This happens due to the carbon-fluorine bond breaking. The sp3 hybridised structure of the fluorinated graphene is reduced back into the sp2 hybridised structure of pristine graphene. The superconducting properties of molybdenum-rhenium are characterised. It is shown to have a transition temperature of 7.5 K. It is also discovered that the material has a resistance to hydrofluoric acid; the acid etches nearly all other superconducting materials. This makes MoRe a possible candidate to explore superconductivity in conjunction with high mobility suspended graphene. To see if the material is compatible with graphene, a supported Josephson junction is fabricated. A proximity induced super current is sustained through the junction up to biases of ∼ 200 nA. The temperature dependence of the conductivity is measured for both suspended MoS2 and WS2 on a hexagonal boron nitride substrate. The dominant hopping mechanism that contributes to the conductivity at low temperatures is found to be Mott variable range hopping, with the characteristic T−1/3 dependence. The hopping transport is due to impurities that are intrinsic to the crystals, this is confirmed by comparing the results with those of supported devices on SiO2.
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Patz, Timothy Matthew. "Laser Processing of Biological Materials." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7451.
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I have explored the use of the matrix assisted pulsed laser evaporation (MAPLE) and MAPLE direct write (MDW) to create thin films of biological materials. MAPLE is a novel physical vapor deposition technique used to deposit thin films of organic materials. The MAPLE process involves the laser desorption of a frozen dilute solution (1-5%) containing the material to be deposited. A focused laser pulse (~200 mJ/cm2) impacts the frozen target, which causes the solvent to preferentially absorb the laser energy and evaporate. The collective action of the evaporated solvent desorbs the polymeric solute material towards the receiving substrate placed parallel and opposite to the target. The bioresorbable polymer PDLLA and the anti-inflammatory pharmaceutical dexamethasone were processed using MAPLE, and characterized using Fourier transform infrared spectroscopy, atomic force microscopy and x-ray photoelectron spectroscopy. MDW is a CAD/CAM controlled direct writing process. The material to be transferred is immersed in a laser-absorbing matrix or solution and coated onto a target or support positioned microns to millimeters away from a receiving substrate. Using a UV microscope objective, a focused laser pulse is directed at the backside of the ribbon, so that the laser energy first interacts with the matrix at the ribbon/matrix interface. This energy is used to gently desorb the depositing material and matrix onto the receiving substrate. I have deposited neuroblasts within a three-dimensional extracellular matrix. These two laser processing techniques have enormous potential for functional medical device and tissue engineering applications.
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Liu, Lilin. "Materials science in pre-plated leadframes for electronic packages /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?MECH%202006%20LIUL.
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Miyajima, Shumpei. "Novel deposition of doped amorphous silicon and related materials." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337909.
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Paus, K. "The electron microscopy of silicon of sapphire materials." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382598.
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Xu, Wei-Hua. "Mechanical properties of materials at micro/nano scales /." View abstract or full-text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20XU.
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Chu, Sze Shing. "The electrical and thermal properties of Sb[subscript 1-x]Si[subscript x], Zn[subscript x](SiO[subscript 2])[subscript 1-x] and Ag[subscript x](PrBa[subscript 2]Cu[subscript 3]O[subscript 7])[subscript 1-x] granular films /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202008%20CHU.
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Silverman, Lee Arnold 1959. "Sol-gel derived tantalum oxide thin films." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14835.
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Chen, Weize 1966. "Metrology of very thin silicon epitaxial films." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/17469.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.Includes bibliographical references (p. 161-169).
In this thesis, non-destructive thickness measurement of sub-0.5 µm silicon epitaxial films has been successfully performed using spectroscopic ellipsometry (SE) in the visible to near infrared (NIR) range (0.73 - 3.3 eV). The undoped epitaxial .films are grown on heavily doped substrates by chemical vapor deposition at 700 - 900° C. The effect of heavy doping on the optical properties of crystalline silicon in the spectral range 0.73 - 3.3 eV is precisely described by the Drude free carrier model. It is shown that visible-NIR SE can simultaneously determine the substrate dopant concentration, the thicknesses of epitaxial film and native oxide, and if present, the thickness of the transition layer between the epitaxial film and the substrate. The epitaxial film thicknesses measured by visible-NIR SE are in excellent agreement with results of secondary ion mass spectrometry (SIMS). The substrate dopant concentrations measured by SE also agree well with SIMS results for n-type substrates, but are consistently higher than SIMS values for p-type substrates. It is also demonstrated that visible-NIR SE is very sensitive to the epi/substrate interface quality therefore can be used for process monitoring in low temperature silicon epitaxy. Non-destructive determination of thickness and composition of strained Si1-xGex (0 < x 0.30) heteroepitaxial layers has also been successfully carried out in this thesis using visible-NIR SE. The dielectric function of the Sii-xGex layers in the spectral range 0. 75 - 2. 75 e V is fitted to a self-consistent empirical formula with only five fitting parameters. Accurate ellipsometry measurement of thickness and composition is successfully demonstrated using this formula. This thesis has developed a non-destructive technique for the measurement of both silicon and Sii-xGex epitaxial films. This technique is suitable and can be easily implemented for in-line, in situ and real-time measurement. This study also provides a numerical expression for the optical constants of strained Si1-xGex in the spectral range of interest for most optoelectronic applications.
by Weize Chen.
Ph.D.
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Young, David Y. "Electrochemical H insertion in Pd thin films." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/122864.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 51-55).
Metal hydrides are pertinent to several applications, including hydrogen storage, gas separation, and electrocatalysis. The Pd-H system is used as a model for metal-hydrogen systems and the effect H insertion has on their properties. A study was conducted to assess the performance of various electrochemical cell formats in electrochemically inserting H into Pd, which is important in building devices for the above applications. A set of in situ X-ray diffraction apparatuses were built to enable simultaneous electrochemical H insertion and measurement of PdH[subscript x] composition. A comparison between aqueous and solid electrolytes, temperature, and thin film vs. bulk Pd revealed that thinner films, lower temperatures, and aqueous electrolytes tended to promote higher achievable H content, with the highest H:Pd ratio observed being 0.96 ± 0.02. These results not only show high H loading into Pd but also both reproducibility and a clear association between varied parameters and cell performance. In addition, the stability and performance of high temperature solid oxide electrolytes was investigated. A novel in situ calorimeter was constructed to enable the study of high temperature solid oxide electrolyte degradation while under operating conditions, similar to recent work in calorimetric analysis of battery stability. This calorimeter has a power detection sensitivity of 16.1 ± 11.7 mW, which is sufficient for detecting and quantifying many of the degradation and other side reactions that occur during high temperature operation of a solid oxide electrolyte in an electrochemical cell. This apparatus provides a tool needed to assess stability and life of solid oxide electrolytes under operation, a critical component to developing higher performing solid oxide electrochemical devices.
by David Y. Young.
S.M.
S.M. Massachusetts Institute of Technology, Department of Materials Science and Engineering
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Gupta, Manish. "Simulation and Analysis of Thin Strip Casting Process." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391676878.
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Suddendorf, Manfred B. "Laser scanning probes for thermal wave materials characterisation and microscopy." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239553.
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Gray, Dilys Eira. "Static and dynamic studies of materials and processes using ellipsometry." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242187.
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Omar, Ozma. "Optical effects in Langmuir-Blodgett films of novel organic materials." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/20143/.
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The high level of molecular control makes the Langmuir-Blodgett (LB) technique an appealing method of film deposition. The uniform nature of the films produced allows convenient investigation of intermolecular interactions and provides information pertaining to the orientation of molecules within films. LB films of two amphiphilic materials with contrasting molecular structures have been deposited. AmPc5 (a metal-free phthalocyanine (pc)) is a two-dimensional, cyclic molecule, whereas AmAzl (a resorcinol calixarene) possesses a three-dimensional basket-type structure. The amphiphilic nature of both molecules is as a result of functional side-chains. The AmPc5 spreading solution was prepared by dissolving in trichloroethane to a concentration of 0.1 mg/ml. After spreading 500-600 ul, the resulting Langmuir film was found to have a critical pressure of 28 mN/m and an area per molecule of 1.61 nm2 on the water surface. Monolayer deposition onto glass substrates enabled spectroscopic examination of the films and comparison to solution spectra. The solution spectrum shows the split Q-band absorption peaks at 700 nm and 733 nm characteristic of metal-free pc's. The LB film spectrum shows a broadening of both peaks and a red shift of the 733 nm peak, and a blue shift of the 700 nm peak. The 700 nm peak is suppressed as a result of the stack-like packing structure of AmPc5. Absorption spectra of floating AmPc5 monolayers imply that the material does not assume the monomer state at any stage of compression. This is characteristic of rigid molecules that induce order within the floating monolayer. The refractive indices (n) and extinction coefficients (k) were determined across the visible wavelength range. Both the n and k values are shown to increase with monolayer thickness, although the n value tends towards a steady value of 2.1. Deposition onto gold coated glass substrates enabled surface plasmon resonance analysis and determination of n and k at specific film thickness'. The n was found to increase with film thickness, tending towards a steady state value of 2.0. This is in excellent agreement with spectroscopic analysis. Absorption spectra measured using polarised light show AmPc5 exhibits dichroism. The calculations indicate that the pc ring lies almost perpendicular to the substrate. AmAzl was dissolved in chloroform to a concentration of 0.5 mg/ml with 10% ethanol to aid solubility. The optimum solution spreading quantity required to form a floating monolayer was found to be between 50 and 100 ul. The film was shown to have a critical pressure of 30 mN/m and an area per molecule of 1.86 nm2 on the water surface. Both LB film and solution spectra show a single absorbance peak at 454 nm which is due to transitions in the azo functional side chains. Calculation of n and k shows that they tend towards steady values of 1.5 and 2.0, respectively. The n obtained via surface plasmon resonance analysis shows a steady state value of 1.43 on silver coated glass and 1.35 on gold coated glass. This suggests a different type of packing structure on all three substrates. The lack of dichroism exhibited by AmAzl indicates the formation of in-plane amorphous films. AmAzl was deposited in alternating layers with tricosenoic acid. The structure was confirmed by X-ray diffraction studies and investigated using second harmonic generation. The second harmonic signal was shown to be proportional to the square of the number of bilayers.
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Ma, Yunfei. "Micromagentic [sic] study of magnetoeleastic materials /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/7068.
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Holder, Simon James. "The synthesis and evaluation of cyclic and linear polysiloxane Langmuir-Blodgett materials." Thesis, University of Hull, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318703.
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