Dissertations / Theses on the topic 'Thin films'

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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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2

Mackay, Ian. "Thin film electroluminescence /." Online version of thesis, 1989. http://hdl.handle.net/1850/10551.

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3

Tam, Dickson Tai Shun. "An investigation on effect of Mn-doping on dielectric property of barium strontium stannate titanate." access abstract and table of contents access full-text, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?msc-ap-b21175135a.pdf.

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Thesis (M.Sc.)--City University of Hong Kong, 2005.
At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 4, 2006) Includes bibliographical references.
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4

Yeung, Kwok Fai. "An investigation on effect of Mn-doping on dielectric property of barium strontium stannate titanate." access abstract and table of contents access full-text, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?msc-ap-b21175317a.pdf.

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Thesis (M.Sc.)--City University of Hong Kong, 2005.
At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 4, 2006) Includes bibliographical references.
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5

Wallace, Anthony James. "Tin oxide thin films." Thesis, Brunel University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294556.

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6

Poulter, Mark W. "Pyroelectric organic thin films." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303623.

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7

Kamhawi, Khalid. "Transport in Thin Films." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508624.

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8

Babkair, S. S. "Multilayer ferromagnetic thin films." Thesis, University of Salford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234564.

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9

Hu, Xiao. "Ultra-thin oxide films." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:d7373376-84f1-459e-bffb-f16ce43f02b7.

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Oxide ultra-thin film surfaces have properties and structures that are significantly different from the terminations of the corresponding bulk crystals. For example, surface structures of epitaxial ultra-thin oxide films are highly influenced by the crystallinity and electronegativity of the metal substrates they grown on. Some enhanced properties of the novel reconstructions are related to catalysis, sensing and microelectronics, which has resulted in an increasing interest in this field. Ultra-thin TiOx films were grown on Au(111) substrates in this work. Two well-ordered structures within monolayer coverage - honeycomb (HC) and pinwheel - were generated and investigated. Special attention has been paid to the uniform (2 x 2) Ti2O3 HC phase including its regular structure and imperfections such as domain boundaries (DBs) and point defects. Linear DBs with long-range repeating units have been observed; density functional theory (DFT) modelling has been used to simulate their atomic structures and calculate their formation energies. Rotational DBs/defects show up less frequently, however a six-fold symmetrical 'snowflake' DB loop stands out. Two types of point defects have been discovered and assigned to Ti vacancies and oxygen vacancies/hydroxyl groups. Their diffusion manners and pairing habits have been discussed within an experimental context. The results of growing NbOx ultra-thin films on Au(111) are also presented in this thesis. An identical looking (2 x 2) HC structure to the Ti2O3 ultra-thin film has been formed; a stoichiometry of Nb2O3 is suggested. Another interesting reconstruction is a hollow triangle structure. Various sizes have been found, and sides of these equilateral triangles all show a double-line feature aligned along the { 1 ₁⁻ } directions of the Au(111) lattice. Chemical composition characterisations of NbOx thin films are still required as is DFT modelling. Experimental techniques used in this thesis include scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS). Ultra-thin oxide films were created by physical vapour deposition (PVD) in ultra-high vacuum (UHV) systems.
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10

Campbell-Rance, Debbie. "Electrodeposited Silica Thin Films." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2123.

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Sol-gel derived silica thin film synthesis has gained prominence because of the mild processing conditions and widespread understanding of the chemistry of the process. Traditionally, silicate films are prepared by spin- and dip-coating but these materials lack the desired porosity for sensing, separations and catalysis applications. Electrochemical deposition was proposed to improve the porosity of silicate films. The main aims of this work were threefold. First we wanted to elucidate what parameters influenced film formation during electrodeposition. Then we wanted to understand how these parameters affected the morphology of the materials prepared. These films were characterized by profilometry, AFM, and SEM-EDX. Films electrodeposited via cathodic potentials are particle-like, thicker and rougher than spin-coated films. The final goal was to pattern a substrate with silica using photolithography, sol-gel process and electrodeposition. Successful patterning was hindered by the deposition of silica on glass, especially when the gap between ITO bands was smaller than the diffusion layer thickness of the electroactive species.
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11

Morris, Gareth David Morte. "Particle stabilised thin films." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6206.

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Froth flotation is widely used by the mining industry to concentrate low grade metal ores. It uses the differences in surface properties between particles of the desired mineral and waste material to separate them using a mineralised froth. The properties of this particle stabilised mineralised froth impact on the efficiency of the separation process. Due to its dynamic and unstable nature it is difficult to study and remains relatively poorly understood. A deeper insight into the fundamental froth properties can be gained by using computer modelling techniques. Here a series of models are developed using the Surface Evolver (Brakke 1992). They are used to investigate the effects of particle shape, hydrophobicity and packing arrangement on the critical capillary pressure of thin films. Three dimensional simulations of uniformly spaced spherical particles in the film are compared to existing two dimensional (2D) analytical models. It is shown that 2D models over predict the capillary pressure required to rupture the film. The models are developed further to simulate randomly distributed particles in a periodic film. The results are then used to derive an expression for film stability based on particle packing density and contact angle. The different possible failure modes of double layers of particles are also investigated and the conditions under which they occur identified. A versatile model for simulating non-spherical particles in an interface or film is also derived and used to find the energetically stable orientations of orthorhombic particles at an interface. This information is then used to investigate the effect of particle orientation on the capillary pressure required to rupture the film. It is shown that the combination of contact angle and shape affect the particle orientation. Certain orientations are then shown to reduce the critical capillary pressure of the film by up to 70 %.
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12

CHIPMAN, RUSSELL ATWOOD. "POLARIZATION ABERRATIONS (THIN FILMS)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184051.

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Polarization aberrations are the variations of amplitude, phase, polarization and retardance associated with ray paths through optical systems. This dissertation develops methods for calculating the polarization aberrations of radially symmetric systems of weak polarizers, systems like lenses, telescopes and microscopes. The instrumental polarization in these systems arises from weak polarization effects occurring near normal incidence at glass, metal and thin film coated interfaces. Polarized light and polarizers are treated using the Jones calculus. Weak polarizers, optical elements with small polarization effects, are treated by expanding the Fresnel equations and thin film equations into a Taylor series. Methods are given for calculating the Taylor series coefficients for a multilayer coated interface whose polarization performance is known, for example from a thin film design program. Equations are derived for the propagation of polarized light through optical systems. Weak polarizers are shown to be very weakly order dependent; this greatly facilitates the calculation of the effect of a sequence of weak polarizers. The dominant terms are order independent polarization terms which are readily calculated. The order dependent portion can be systematically evaluated as higher order terms. The instrumental polarization, being a function of angle of incidence, is different for different rays through the system. Thus an optical system is a spatially varying polarizer. The instrumental polarization associated with a single surface is often well approximated as a "parabolic" polarizer. The instrumental polarization function is calculated as a Taylor series Jones matrix about the optical axis as a function of object and pupil coordinates. The resulting spatial variations of the instrumental polarization function bear a strong resemblance to the wavefront aberrations, since both arise from fundamental geometrical considerations. In particular, there are terms in the weak linear polarization and in the weak retardance of radially symmetric systems which strongly resemble defocus, tilt and piston error. A polarization aberration expansion is defined to second order in the object and pupil coordinates. A method is derived for calculating the polarization aberration coefficients for a sequence of radially symmetric surfaces from the Taylor series representation of the polarization associated with the individual interfaces.
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13

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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14

Morasch, Kevin R. "Nanoindentation induced thin film fracture." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Spring2005/k%5Fmorasch%5F042605.pdf.

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15

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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16

Masson, Jean-Loup Didier. "Pattern formation and evolution in thin polymer films." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3034981.

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17

Tannenbaum, Jared Michael. "The development of a portable instrumented indentation system." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5931.

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Thesis (M.S.)--West Virginia University, 2008.
Title from document title page. Document formatted into pages; contains xiv, 127 p. : ill. Includes abstract. Includes bibliographical references (p. 61-62).
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18

Göktaş, Oktay Güneş Mehmet. "Subgap Absorption Spectroscopy In Microcrystalline Silicon Thin Films/." [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/fizik/T000461.pdf.

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19

Ng, Hoi-pang. "Mechanical and electrical properties of nickel-aluminium thin films /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21852315.

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20

Geddis, Demetris Lemarcus. "Single fiber bi-directional OE links using 3D stacked thin film emitters and detectors." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180141/unrestricted/geddis%5Fdemetris%5Fl%5F200312%5Fphd.pdf.

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21

Dürr, Arndt Christian. "Growth and structure of DIP thin films and Au contacts on DIP thin films." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10277647.

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22

Peterson, Sarah M. "Influence of scale, geometry, and microstructure on the electrical properties of chemically deposited thin silver films /." Connect to title online (ProQuest), 2007. http://proquest.umi.com/pqdweb?did=1453183211&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2007.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 95-101). Also available online in ProQuest, free to University of Oregon users.
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23

Serral, Serra Maria. "Modeling of thin polymer films." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/306133.

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Aquest treball es centra en l’estudi de dos sistemes diferents de films polimèrics. En primer lloc, s’analitza experimentalment la resposta viscoelàstica dels films polimèrics multicapa (sandvitxos) de polietilè lineal de baixa densitat (LLDPE) i etilen-vinil-alcohol (EVOH). A partir de les dades experimentals es troba que la resposta mecànica dels sandvitxos estudiats es pot predir mitjançant una regla additiva utilitzant les dades dels components purs, quan aquests han estat processats en les mateixes condicions. Per tant, la resposta no depèn del gruix de les capes individuals, ni dels efectes interfacials, sinó només de la fracció volumètrica d’EVOH i LLDPE en el sistema. Es proposa addicionalment un model més mesoscòpic per la resposta viscoelàstica dels films de LLDPE i EVOH purs i els sandvitxos. Aquest es basa en el model de Maxwell Generalitzat que correspon a l’analogia mecànica de la resposta complexa del material. Mitjançant l’ajust del model a les dades experimentals podem obtenir informació sobre l’espectre dels temps de relaxació, els quals ens donen coneixement sobre l’estructura microscòpica del sistema. Finalment, el segon sistema que s’investiga és completament diferent a l’anterior. Aquest sistema consisteix en films de “diblock-copolymers” que formen esferes i que estan sotmesos a influències externes. Per l’estudi s’utilitza una implementació numèrica de la dinàmica del sistema en una xarxa que es coneix com “Cell Dynamics Simulation”. A través de les simulacions demostrem que podem obtenir formacions de dominis esfèrics altament ordenats en films prims sobre una superfície químicament decorada amb bandes paral•leles. No obstant, l’ordre de llarg abast, requerit en aplicacions nanoscòpiques, depèn de la commensurabilitat de l’estructura amb la periodicitat de les bandes i el gruix del film, i la seva adequada selecció permet tenir una disposició d’esferes hexagonal o bé quadrada, que correspondria a un empaquetament cúbic centrat (BCC).
Este trabajo se centra en el estudio de dos sistemas diferentes de films poliméricos. En primer lugar, se analiza experimentalmente la respuesta viscoelástica de los films poliméricos multicapa (sándwiches) de polietileno lineal de baja densidad (LLDPE) y etilen-vinil-alcohol (EVOH). Partiendo de los datos experimentales se encuentra que la respuesta mecánica de los sándwiches se puede predecir mediante una regla aditiva utilizando los datos de los componentes puros, cuando éstos han sido procesados en las mismas condiciones. Por consiguiente, la respuesta no depende del grosor de las capas individuales, ni de los efectos interfaciales, sino que depende de la fracción volumétrica de EVOH y LLDPE en el sistema. Se propone adicionalmente un modelo más mesoscópico para la respuesta viscoelástica de los films de LLDPE y EVOH puros y los sándwiches. Éste se basa en el modelo de Maxwell Generalizado que corresponde a la analogía mecánica de la respuesta compleja del material. Mediante el ajuste del modelo a los datos experimentales podemos obtener información sobre el espectro de los tiempos de relajación, que nos dan conocimiento sobre la estructura microscópica del sistema. Finalmente, el segundo sistema que se investiga es completamente diferente al anterior. Este sistema consiste en filmes de “diblock-copolymers” que forman esferas y se someten a influencias externas. Para el estudio se utiliza una implementación numérica de la dinámica del sistema en una red conocida como “Cell Dynamics Simulation”. Por medio de las simulaciones demostramos que se pueden obtener formaciones de dominios esféricos altamente ordenados en films delgados sobre una superficie químicamente decorada con bandas paralelas. El orden de largo alcance depende de la conmensurabilidad de la estructura con la periodicidad de las bandas y del grosor del film, y su adecuada selección permite tener una disposición de esferas hexagonal o bien cuadrada, correspondiente a un empaquetamiento cúbico centrado (BCC).
This work is focused on the study of two different systems of thin polymeric films. In the first place, the viscoelastic response of multilayer polymeric films (sandwiches) of linear low-density polyethylene (LLDPE) and ethylene vinyl alcohol (EVOH) copolymer has been experimentally analyzed. From experimental data we find that the mechanical response of the studied sandwiches can be predicted through a mixing rule using the data of the pure constituents when they have been processed under the same conditions. Then, the response does not depend on the individual layer thickness, neither on the interfacial effects, but only on the volume fraction of the EVOH and LLDPE in the system. We additionally propose a more mesoscopic model for the viscoelastic response of the solid LLDPE and EVOH films and sandwiches. The model is formally a Generalized Maxwell (GM) model, which corresponds to a mechanical analog of the complex response of the material. Through the fitting of the model to the experimental data one can get information on the spectra of relaxation times, which bear information on the microscopic structure of the system. Finally, the second system investigated is completely different to the previous one. This system studied consists of films of sphere-forming diblock copolymers under external influences. For the study we use a numerical implementation of the dynamics of the system on a lattice that is referred to as Cell Dynamics Simulation. Using 3-Dimensional CDS we demonstrate that on patterned surfaces with chemically attractive parallel stripes, arrays of spherical domains with long-range order, required for nanoscopic applications, can be obtained. The long-range order depends on the commensurability of the structure with both the band periodicity and slit thickness, and their proper selection permits the system to switch from a hexagonal packing to a square packing corresponding to a body-centered orthohedron.
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Hänni-Ciunel, Katarzyna. "Interactions in thin aqueous films." [S.l.] : [s.n.], 2006. http://opus.kobv.de/tuberlin/volltexte/2006/1432.

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Huang, Bin. "Mechanical characterization of thin films /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20HUANG.

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Song, Gang. "Hydrogen in thin niobium films." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961906529.

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Kedsongpanya, Sit. "Nanolaminated Thin Films for Thermoelectrics." Thesis, Linköping University, Linköping University, Department of Physics, Chemistry and Biology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-56699.

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Energy harvesting is an interesting topic for today since we face running out of energy source, a serious problem in the world. Thermoelectric devices are a good candidate. They can convert heat (i.e. temperature gradient) to electricity. This result leads us to use them to harvest waste heat from engines or in power plants to generate electricity. Moreover, thermoelectric devices also perform cooling by applied voltage to device. This process is clean, which means that no greenhouse gases are emitted during the process. However, the converting efficiency of thermoelectrics are very low compare to a home refrigerator. The thermoelectric figure of merit (ZTm) is a number which defines the converting efficiency of thermoelectric materials and devices. ZTm is defined by Seebeck coefficient, electrical conductivity and thermal conductivity. To improve the converting efficiency, nanolaminated materials are good candidate.

 

This thesis studies TiN/ScN artificial nanolaminates, or superlattices were grown by reactive dc magnetron sputtering from Ti and Sc targets. For TiN/ScN superlattice, X-ray diffraction (XRD) and reciprocal space map (RSM) show that we can obtain single crystal TiN/ScN superlattice. X-ray reflectivity (XRR) shows the superlattice films have a rough surface, supported by transmission electron microscopy (TEM). Also, TiN/ScN superlattices grew by TiN as starting layer has better crystalline quality than ScN as starting layer. The electrical measurement shows that our superlattice films are conductive films.

 

Ca-Co-O system for inherently nanolaminated materials were grown by reactive rf magnetron sputtering from Ca/Co alloy target. The XRD shows we maybe get the [Ca2CoO3]xCoO2 phase, so far. The energy dispersive X-ray spectroscopy (EDX) reported that our films have Al conmination. We also discovered unexpected behavior when the film grown at high temperature showed larger thickness instead of thinner, which would have been expected due to possible Ca evaporation. The Ca-Co-O system requires further studies.

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Kobler, Johannes. "Thin Films from Porous Nanoparticles." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-98694.

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Ross, Caroline Anne. "Electromigration in thin metal films." Thesis, University of Cambridge, 1989. https://www.repository.cam.ac.uk/handle/1810/250938.

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Ma, Fuyuan. "Electrochemically active organic thin films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0020/NQ44501.pdf.

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Pradhan, Sailesh. "Tensile testing of thin films /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1203573161&sid=10&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (M.S.)--Southern Illinois University Carbondale, 2006.
"Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (leaves 73-84). Also available online.
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Music, Denis. "Boron suboxide based thin films /." Linköping : Univ, 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/tek835s.pdf.

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Yim, Sanggyu. "Structure of phthalocyanine thin films." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405780.

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Mohd, Yatim Yazariah. "Unsteady flows of thin films." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=14374.

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Bunce, Christopher Edward. "Magnetisation dynamics in thin films." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495860.

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Lin, Keng-Yu. "Thin films for thermoeletric applications." Thesis, Linköpings universitet, Tunnfilmsfysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-109106.

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Global warming and developments of alternative energy technologies have become important issues nowadays. Subsequently, the concept of energy harvesting is rising because of its ability of transferring waste energy into usable energy. Thermoelectric devices play a role in this field since there is tremendous waste heat existing in our lives, such as heat from engines, generators, stoves, computers, etc. Thermoelectric devices can extract the waste heat and turn them into electricity. Moreover, the reverse thermoelectric phenomenon has the function of cooling which can be applied to refrigerator or heat dissipation for electronic devices. However, the energy conversion efficiency is still low comparing to other energy technologies. The efficiency is judged by thermoelectric figure of merit (ZT), defined by Seebeck coefficient, electrical conductivity and thermal conductivity. In order to improve ZT, thin film materials are good candidates because of their structural effects on altering ZT.    Ca3Co4O9 thin films grown by reactive radio frequency magnetron sputtering followed by post-annealing process is studied in this thesis. Structural properties of the films with the evolution of elemental ratio (Ca/Co) of calcium and cobalt have been investigated. For the investigations, three samples having elemental ratio 0.82, 0.72, and 0.66 for sample CCO1, CCO2 and COO3, respectively, have been prepared. Structural properties of the films have been investigated by X-ray diffraction (XRD) θ-2θ and pole figure analyses. Surface morphology of the films has been investigated by scanning electron microscopic (SEM) analyses. The highly oriented and phase pure epitaxial Ca3Co4O9 thin films were obtained in the end.   Mixing of ScN and CrN to obtain ScxCr1-xN solid solution thin films by DC magnetron sputtering is the other task in this thesis. Growth of ScN and CrN thin films were studied first in order to get the best mixed growth conditions. The phase shifts between ScN (111) and CrN (111) peaks were observed in mixed growth films by XRD θ-2θ measurements, indicating the formation of ScxCr1-xN. Surface morphology of the films were investigated by SEM. The (111)-oriented ScxCr1-xN thin films with decent surface smoothness grown by DC magnetron sputtering at 600 °C in pure nitrogen with bias were developed.
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Karl, Werner Josef. "Piezomagnetic thin-films and devices." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425487.

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Adamjee, Admil. "Ormosil thin films for waveguides." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301907.

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39

Logan, Randy. "Optical metrology of thin films." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46094.

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40

Song, Ohsung. "Magnetoelastic coupling in thin films." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/28083.

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41

Aessopos, Angelica. "Surfactant instabilities on thin films." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/88902.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
"June 2005."
Includes bibliographical references (pages 89-92).
The deposition of a surfactant drop over a thin liquid film may be accompanied by a fingering instability. In this work, we present experimental results which identify the critical parameters that govern the shape and extend of the fingering phenomena. It was found that the normalized wavelength, [lambda]/t, scales with Marangoni number, Ma=[Delta][gamma]t/[mu]D, to the -1 exponent for any Marangoni higher than 4.3 · 10⁷. On the other end, for Marangoni < 4.3 · 10⁷ the normalized wavelength scales with Ma to the -0.4 but becomes in addition a funcion of the Prandtl number, Pr=[upsilon]/D, which demonstrates the critical significance of bulk diffusion on the spreding behavior. Finally, we present a numerical implementation of a mathematical model which is capable of reproducing the experimentally observed trends.
by Angelica Aessopos.
S.M.
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42

Marshall, J. M. "Thin lead zirconate titanate films." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/10743.

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The subject of study was the growth and nucleation of sol-gel deposited lead zirconate titanate (PZT) films of composition Pb(Zr0_52,Ti0_4g)O3 (PZT52/48). This particular composition is on a phase boundary between titanium-rich tetragonally structured PZT and the zirconium-rich rhombohedral phase. The coexistence and relative instability of these phases is thought to be one of the origins of high piezoelectric coefficients exhibited by films of this composition. The aims of this study were to investigate variables affecting the piezoelectric coefficients in sol-gel deposited PZT52/48 thin films. Control of preferred orientation if PZT52/48 films on platinum-coated substrates was accomplished by manipulating processing conditions, specifically pyrolysis temperature. Corona poling was investigated as an alternative to contact poling. Attempts were made to find a set of poling parameters which yielded consistent results. Piezoelectric coefficients are highly dependant on poling conditions, with coefficient being lower in insufficiently poled films or those damaged by field induced sample cracking. It was observed that (001)/(100)-oriented samples with small grains had significantly lower piezoelectric coefficients and were harder to pole than coarser-grained (00l)/(l00)- oriented samples. Samples with a more irregular grain structure and a wide distribution of grain size had the lowest piezoelectric coefficients, irrespective of preferred orientation. The impact of grain size on piezoelectric coefficients was confirmed using the FWHM of the (200) reaction. Films with more irregular grain structures had higher FWHM than those with more uniform grains and had lower d33,f and e31,f. Values of e31,f and d33f were plotted against (001) intensity a determined from xray diffraction. It was difficult to determine any correlation between piezoelectric coefficients and (001) intensity. I comparison, there was a definite inverse correlation between d33,f, e31,f and FWHM, indicating that defect concentration has much more of an impact on piezoelectric coefficients in polycrystalline thin films than (001) intensity as a result of defect-induced domain pinning.
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43

Д`яченко, Олексій Вікторович, Алексей Викторович Дьяченко, Oleksii Viktorovych Diachenko, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, D. Nam, and H. Cheong. "Characterization Cupper Oxide thin films." Thesis, Львівський національний університет ім. Івана Франка, 2015. http://essuir.sumdu.edu.ua/handle/123456789/48287.

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For obtaining of the CuO thin films have used spray pyrolysis method. Glass plates were cleaned in ultrasonic bath and washed with ethanol, used as a substrates. We used an aqueous solution of copper chloride (CuCl22H2O) with a concentration of 0.05 M as a precursor. The substrate temperature range from 570 to 720 K, with step Т=50 K. For atomization of precursor the air flow with a pressure of 0.25 MPa was used.
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44

Shu, Rui. "Nonstoichiometric Multicomponent Nitride Thin Films." Licentiate thesis, Linköpings universitet, Tunnfilmsfysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-170529.

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High entropy ceramics have rapidly developed as a class of materials based on high entropy alloys; the latter being materials that contain five or more elements in near-equal proportions. Their unconventional compositions and chemical structures hold promise for achieving unprecedented combinations of mechanical, electrical and chemical properties. In this thesis, high entropy ceramic films, (TiNbZrTa)Nx were deposited using reactive magnetron sputtering with segmented targets. The stoichiometry x was tuned with two deposition parameters, i.e., substrate temperature and nitrogen flow ratio fN, their effect on microstructure and mechanical, electric, and electrochemical properties were investigated. Understoichiometric MeNx (Me = TiNbZrTa, 0.25 ≤ x ≤ 0.59) films were synthesized at a constant fN when substrate temperature was varied from room temperature (RT) to 700 °C. For low-temperature deposition, the coatings exhibited fcc solid-solution polycrystalline structures. A NaCl-type structure with (001) preferred orientation was observed in MeN0.46 coating deposited at 400 ºC, while an hcp structure was found for the coatings deposited above 500 ºC. The maximum hardness value of 26 GPa as well as the highest   and   values (0.12 and 0.34 GPa) were obtained for the MeN0.46 coating. These films exhibited low RT electrical resistivities. In 0.1 M H2SO4 aqueous solution, the most corrosion resistant film was MeN0.46 featured dense structure and low roughness. The MeNx films (x=0, 0.57 < x ≤ 0.83) were deposited with different fN. The maximum hardness was achieved at 22.1 GPa for MeN0.83 film. Their resistivities increased from 95 to 424 μΩcm with increasing nitrogen content. The corrosion resistance is related to the amount of nitrogen in the films. The corrosion current density was around 10-8 A/cm2, while the films with lower nitrogen contents (x < 0.60) exhibited a nearly stable current plateau up to 4.0 V, similar to the metallic films, while the films with a higher nitrogen content only featured a plateau up to 2.0 V, above which a higher nitrogen content resulted in higher currents. The reason was that the oxidation of these films at potentials above about 2.0 V vs. Ag/AgCl resulted in the formation of porous oxide layers as significant fraction of the generated N2 was lost to the electrolyte. Hence, these observed effects of deposition temperature and nitrogen content on the overall properties of nonstoichiometric MeNx films provide insights regarding protective multicomponent nitride films, e.g. as corrosion resistant coatings on metallic bipolar plates in fuel cells or batteries.
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45

JOTHIMUTHU, PREETHA. "Photodefinable Polydimethylsiloxane (PDMS) Thin Films." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212181335.

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46

Qureshi, Uzma. "Host thin films incorporating nanoparticles." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1446050/.

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The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful properties photocatalysis, photo-induced super-hydrophilicity and thermochromism.
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47

Morales, Morales Oswaldo [UNESP]. "Construção e caracterização de células solares de filmes finos de CdS e CdTe." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/91965.

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Neste trabalho, o objeto de estudo foi células Solares CdS/CdTe. Estas células usam o filme de sulfeto de cádmio (CdS) como semicondutor do tipo n e o filme de telureto de cádmio (CdTe) como semicondutor do tipo p. O recorde mundial, alcançado no laboratório, para estas células é 16,5% de eficiência. Nos Laboratórios do Departamento de Física e Química de Unesp - Ilha Solteira, este trabalho é pioneiro na fabricação de Células Solares de CdS/CdTe. Para realizar este trabalho foi necessário melhorar o sistema de deposição por spray de SnO2:F já existente, acondicionar o sistema de banho químico para deposição do filme de CdS e implementar o sistema de sublimação para depositar a camada de CdTe. Todos estes sistemas de deposição de filmes finos foram implementados no laboratório do Grupo de Desenvolvimento e Aplicação de Materiais (GDAM). A fabricação da Célula Solar CdS/CdTe consistiu na deposição sequencial sobre vidro de a) Eletrodo condutor transparente utilizando óxido de estanho dopado com Flúor (SnO2:F) pelo método de spray, com controle automático de jato; b) deposição de sulfeto de Cádmio (CdS) pelo método de banho Químico (CBD); c) deposição de Telureto de Cádmio (CdTe) pela técnica de sublimação no espaço fechado (CSS) e d) deposição do contato metálico traseiro de prata por colocação de camada liquida e posteriormente a melhora deste contato com grafite-prata. A estrutura final destas células foi: Vidro/SnO2:F/CdS/CdTe/contato. A caracterização estrutural e óptica das camadas destas células foi realizada pelas técnicas de DRX e UV-vis; os parâmetros elétricos das células foram determinados pela construção da curva I-V. A camada CdTe da célula solar foi tratada termicamente com dicloreto de cádmio (CdCl2) para comparar a sua eficiência com outra célula que não foi tratada...
The object of this work was the study solar Cells CdS/CdTe. These cells use a cadmium sulfide film as an n-type semiconductor and a cadmium telluride film as a p- type semiconductor The world record for maximum efficiency achieved in laboratory for these cells is 16.5%. In laboratories of Departament of Physics and Chemistry of Unesp-Ilha Solteira, this work is a pioneer in the manufacture of CdS/CdTe Solar Cell. To carry out this work it was necessary to improve the existing system of Spray deposition of SnO2: F, conditioning of the system for chemical bath deposition of CdS film and manufacture the sublimation system to deposit the CdTe layer. All of these systems for the deposition of thin films were developed in the laboratory. The manufacture of CdS/CdTe solar cell consisted of sequential deposition on glass of a) transparent conductive tin oxide doped with fluorine (SnO 2:F) using automatic control system of the spray; b) deposition of cadmium sulfide (CdS) for method (CBD); c) deposition of cadmium telluride for technique in closed space sublimation (CSS) and d) the rear metallic contact of silver was deposited by placing the liquid layer and subsequent improvement of contact with graphite-silver. The final structure of cell used in this work was: glass/SnO2:F/CdS/CdTe/contact. The CdTe solar cell layer was heat treated with cadmium dichloride (CdCl2) to compare its efficiency with another cell that was not treated with cadmium dichloride. Then we investigated the performance of only putting back metal contact layer of silver of silver and silver-graphite layer, the latter was giving better results, achieving an efficiency is a well more than 5%
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48

Gonçalves, Thaís Matiello [UNESP]. "Caracterização de filmes finos obtidos por deposição de vapor químico assistido a plasma (PECVD) e deposição e implantação iônica por imersão em plasma (PIIID)." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99671.

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Filmes finos de carbono amorfo hidrogenado contendo silício e dopados com flúor foram produzudos pelos métodos de Deposição de Vapor Químico Assistido e Plasma (PECVD) e Deposição e Implantação Iônica por Imersão em Plasma (PIIID). Para PECVD foi utilizada uma pressão total de gases/vapor de 100 mTorr e inicialmente, 100W de potência de excitação. A proporção dos gases foi estudada, mantendo a concentração do hexametildisiloxano (HMDSO) em 75% e variando a proporção do argônio (Ar) e do hexafluoreto de enxofre (SF6). As porcentagens de flúor utilizadas na alimentação do plasma variaram em 0,6,9 e 12,5%. Visando maior concentração atômica de flúor na estrutura dos filmes, determinou-se a proporção de gases/vapor mais apropriada (75% HMDSO, 19% Ar e 6% SF6), e posteriormente, foi realizado um novo estudo da potência de excitação. Variando a potência entre 40 e 70 W, 50 W foi considerada como sendo a melhor condição de excitação para a descarga luminosa, considerando os efeitos causados pela corrosão relacionada ao flúor e a incorporação do elemento. Um estudo sobre as mesmas proporções foi realizada pela técnica de PIIID, com uma pressão total de 50 mTorr, potência de 50 W e pulsos negativos com magnitude de 800 V. Para este método o filme produzido com 12,5% de SF6 foi escolhido como sendo a melhor opção, tendo em vista que apresentou a maior quantidade atômica de flúor em sua estrutura. Posteriormente, a intensidade dos pulsos aplicados foi variada entre 544 e 14801 V, onde verificou-se que o aumento da intensidade dos pulsos resulta na diminuição da incorporação de flúor
Hydrogenated amorphous carbon films containing silicon and doped with fluorine were produced by two methods: Plasma Enhanced Chemical Vapor Deposition (PECVD) and Deposition (PIIID). For PECVD a total pressure of 100 mTorr was used at a excitation power of 100 W. The gas/vapor proportion was studied, keeping 75% hexamethyldisiloxane and varying the argon (Ar) and sulfur hexafluoride (SF6) ratio. The following proportions of SF6) ratio. The following proportions of SF6 were examined: 0, 6, 9 and 12.5%. Aiming for the highest atomic concentration of fluorine in film structure the best condition (75% HMDSO, 19% Ar and 6% SF6) was determined and a new study of the influence of the radiofrequency power. Considering the corrosion effects gernerated by fluorine in the plasma, variation of the applied power between 40 and 70 W, allowed the selection of 50 W as the best conditions. A study employing the same proportior PIIID was performed using 50 mTorr of total pressure, an applied power of 50 W and a pulse bias of 800 V. Considering the results of the chemical characterizations, films were produced with 12.5% of SF6 in the plasma feed. Subsequently, bias voltage was varied between 544 and 1480 V, where it was observed that the increasing the pulse bias decreased the fluorine concentration in film structure
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49

Silva, Vitor Diego Lima da [UNESP]. "Investigação de contatos elétricos e propriedades de filmes finos de SnO2 dopados com os íons terras raras Eu3+ e Ce3+." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99676.

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O objetivo principal deste trabalho é elucidar quais são os mecanismos de transporte de portadores de carga presentes na interface entre SnO2 e o contato metálico, pois tal conhecimento é fundamental para a aplicação na eletrônica. Além disso, é objetivo aqui também, estudar características de transporte em SnO2 dopado com alguns íons terras-raras. As amostras de SnO2 dopadas em Eu3+ e Ce3+ utilizadas nesta pesquisa foram sintetizadas a partir do método sol-gel e os filmes finos depositados pela técnica dip-coating. Os contatos estudados foram feitos a partir dos metais In, Sn e Al, depositados via evaporação resistiva. Medidas de resistência em função da temperatura nas amostras dopadas com Eu indicaram uma variação significativa da resistividade, de até 10 vezes, quando alterado o metal do contato. Isto se deve a diferença entre a função de trabalho de cada metal, que consequentemente acarreta em variação da barreira de potencial na junção metal-semicondutor. Pela característica das curvas de corrente medida em função da tensão aplicada, observou-se que os dois mecanismos de condução elétrica dominantes na interface são a emisssão termiônica, quando em baixas temperaturas e tensões de menor intensidade, e o tunelamento através da barreira, quando em temperaturas mais altas e tensões de maior intensidade. Com base nesses resultados e na aplicação do método proposto por Rhoderick estimou-se os valores da altura da barreira de potencial na junção metal-semicondutor, em 132 meV, 162 meV e 187 meV para os metais In, Al, Sn, respectivamente. Além disso, o tratamento térmico realizado nas amostras promoveu, de modo geral, a diminuição da resistividade do dispositivo devido, provavelmente, ao estreitamento da barreira de potencial e consequente aumento da...
The main goal of this work is the verification of electrical transport mechanisms of charge carriers at the interface between SnO2 and the metallic contact, because this knowledge is fundamental for electronic applications. Besides, another goal here is to investigate transport characteristics of rare-earth doped SnO2 samples doped with Eu3+ and Ce3+ used in this research were made from the sol-gel method and the thin films were deposited via dip-coating technique. The analyzed contacts were deposited from metals In, Sn and Al, via resistive evaporation technique. Resistance as function of temperature measurements applied to Eu-doped samples indicates a significant resistivity, up to 10 times, when the contact metal is varied. This is due to the differences in the work function of each metal, leading to variation in the potential barrier at interface of the metal-semiconductor junction. The characteristics of the current-voltage curves yield two dominant electrical mechanisms at the interface: thermo-ionic emission, for low temperatures and higher applied bias, and quantum tunneling through the barrier, when the temperature is higher and so is the applied bias magnitude. Based on these results and the application of the method proposed by Rhoderick, the potential barrier height of metal-semiconductor junction values were evaluated, yielding 132 meV, 162 meV and 187 meV for the metals In, Al and Sn, respectively. Besides, generally speaking, thermal annealing promotes the resistivity decrease, probably due to the potential barrier narrowing, increasing the tunneling probability. The variation of Ce3+ concentration, from 0,1% also leads to variation in the device resistivity, but this is not related to the potential at the junction interface, instead it is related with other bulk factors, as the charge... (Complete abstract click electronic access below)
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50

Moffat, Steven H. "Transport and infrared properties of ion irradiated YBa2Cu3O7-8 thin films /." *McMaster only, 1997.

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