Дисертації з теми "Au based alloy nanowires"
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Jiao, Mingzhi. "Microfabricated Gas Sensors Based on Hydrothermally Grown 1-D ZnO Nanostructures." Doctoral thesis, Uppsala universitet, Mikrosystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-320183.
Повний текст джерелаElbasiony, Amr Mohamed Wahba [Verfasser]. "Electrodeposition of tin and tin based alloys from ionic liquids : nanowires, thin films and macroporous structures / Amr Mohamed Wahba Elbasiony." Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2015. http://d-nb.info/107822692X/34.
Повний текст джерелаBurr, Loïc [Verfasser], Christina [Akademischer Betreuer] Trautmann, Ralph [Akademischer Betreuer] Krupke, Robert [Akademischer Betreuer] Stark, and Friedemann [Akademischer Betreuer] Völklein. "Ion-track technology based synthesis and characterization of gold and gold alloys nanowires and nanocones / Loïc Burr. Betreuer: Christina Trautmann ; Ralph Krupke ; Robert Stark ; Friedemann Völklein." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1112269622/34.
Повний текст джерелаJi, Chunxin. "Synthesis, characterization and applications for gold-silver alloy and nanoporous gold nanowires." Available to US Hopkins community, 2002. http://wwwlib.umi.com/dissertations/dlnow/3080690.
Повний текст джерелаSjöberg, Ted. "Plasticity modelling of nickel based super alloy Alloy 718." Licentiate thesis, Luleå tekniska universitet, Material- och solidmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16884.
Повний текст джерелаGodkänd; 2014; 20140115 (tedsjo); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Ted Sjöberg Ämne: Hållfasthetslära/Solid Mechanics Uppsats: Plasticity Modelling of Nickel Based Super Alloy Alloy 718 Examinator: Professor Mats Oldenburg, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Forskare Paul Åkerström, Swerea MEFOS Tid: Fredag den 28 februari 2014 kl 09.00 Plats: E246, Luleå tekniska
Shi, Teng. "Confined States in GaAs-based Semiconducting Nanowires." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460447182.
Повний текст джерелаKockert, Maximilian Emil. "Thermoelectric transport properties of thin metallic films, nanowires and novel Bi-based core/shell nanowires." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/23001.
Повний текст джерелаThermoelectric phenomena can be strongly modified in nanomaterials compared to the bulk. The determination of the electrical conductivity, the absolute Seebeck coefficient (S) and the thermal conductivity is a major challenge for metrology with respect to micro- and nanostructures because the transport properties of the bulk may change due to surface and confinement effects. Within the scope of this thesis, the influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. For this reason, a measurement platform was developed as a standardized method to determine S of a thin film. Structural properties, like film thickness and grain size, are varied. Boundary and surface scattering reduce S of the thin films compared to the bulk. In addition, a method is demonstrated to determine S of individual metallic nanowires. For highly pure and single crystalline silver nanowires, the influence of nanopatterning on the temperature dependence of S is shown. A model allows the distinct decomposition of the temperature-dependent S of platinum and silver into a thermodiffusion and phonon drag contribution. Furthermore, the thermoelectric transport properties of individual bismuth-based core/shell nanowires are investigated. The influence of the shell material (tellurium or titanium dioxide) and spatial dimension of the nanowire on the transport properties are discussed. Scattering at surfaces, indentations and interfaces between the core and the shell reduces the electrical and the thermal conductivity. A compressive strain induced by the shell can lead to a band opening of bismuth increasing S. The core/shell system points towards a route to successfully tailor the thermoelectric properties of bismuth.
Najafi, M., Barmachi N. Rastegar, S. Soltanian, Z. Alemipour, and A. Aftabi. "The Effect of Diameter and Thermal Treatment on Magnetic Properties of Co1-xZnx Alloy Nanowires." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35350.
Повний текст джерелаSansa, Perna Marc. "Characterization of nanomechanical resonators based on silicon nanowires." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/125966.
Повний текст джерелаNanomechanical mass sensors have attracted interest during the last years thanks to their unprecedented sensitivities, which arise from the small dimensions of the resonator which comprises the sensing element. This thesis deals with the fabrication and characterization of nanomechanical resonators for mass sensing applications. This objective comprises three different aspects: 1) the development of a fabrication technology of nanomechanical resonators based on silicon nanowires (SiNW), 2) the characterization of their frequency response by electrical methods and 3) the evaluation of their performance as mass sensors. During this work, we have fabricated nanomechanical resonators based on SiNW clamped-clamped beams, using two different approaches: bottom-up growth of SiNW and top-down definition by lithography methods. By exploiting the advantages of each technique, we have succeeded in fabricating nanowires of small lateral dimensions, in the order of 50 nanometers, and with high number of devices per chip, achieving a high throughput taking into account the dimensions of these structures. We have applied advanced electrical detection schemes based on frequency down-mixing techniques for the characterization of the frequency response of the devices. We have found that the frequency modulation (FM) detection method provides the best efficiency in transducing the mechanical oscillation into an electrical signal. This technique has enabled the detection of multiple resonance modes of the resonator at frequencies up to 590 MHz. The detection of high modes of resonance is important to address one of the issues in nanomechanical mass sensing, decoupling the effects of the position and mass of the deposited species. Moreover, by combining the information obtained from the experimental characterization of the frequency response with FEM simulations, we have quantified the stress accumulated in the SiNWs during the fabrication. We have studied the electromechanical transduction mechanisms in SiNW resonators by the comparative performance of three electrical detection methods: the aforementioned FM and two more detection techniques (namely the two-source, 1ω and the two-source, 2ω). We have proved that two different transduction mechanisms co-exist in bottom-up grown SiNWs: linear (in which the transduced signal is proportional to the motion of the resonator) and quadratic (in which the transduced signal is proportional to the square of the motion of the resonator). On the other hand, in the top-down nanowires only the linear transduction mechanism is present. It is this newly found linear transduction which enables the outstanding performance of the FM detection method when characterizing the frequency response of SiNW resonators. For the use of nanomechanical resonators in mass sensing applications, the real-time tracking of their resonance frequency is needed. We have designed and implemented a novel closed-loop configuration, based on the FM detection technique and a slope detection algorithm. It allows the monitoring of changes in the magnitude and the frequency of the response of the resonator, enabling not only the real time detection of mass, but also the characterization of the temporal stability of the system. In this way, its overall performance for mass sensing applications has been characterized. The mass sensitivity of the system for the smallest resonators stands in the range of 6 Hz/zg (1 zg = 6·10-21 g) and the frequency stability measurements in the closed loop configuration reveal a mass resolution of 6 zg at room temperature.
Hedley, Joseph Henry. "DNA-based conducting polymer nanowires for biosensor applications." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2566.
Повний текст джерелаLiu, Qiong. "Mechanical properties of Ti-o based ceramic nanowires." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/201954/1/Qiong_Liu_Thesis.pdf.
Повний текст джерелаTsourdalakis, Emmanuel. "Phase transformations in Ti3Al based alloy." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28449.
Повний текст джерелаA 'super a2' Ti3Al based alloy with additions of niobium, chromium and tantalum was studied with respect to phase transformation under different heat treatment and aging times and temperatures. As received samples were heated at temperatures ranging between 1000 degrees C ad 1300 degrees C and quenched to retain the high temperature microstructure. Quenched samples were aged between 500 degrees C and 850 degrees C for various times and transformation were studied using dilatometry, x-ray analysis, transmission electron microscopy and microhardness testing. It was found that at around 650 degrees C the transformation of Beta-a2 occurred after two hours of aging, while below this temperature, aging for up to 100 hours at 500 degrees C produced only the Beta-w transformation with very little a2. Also, an 'w-type' phase was observed at this aging temperature. Microhardness measurements and x-ray diffraction confirmed the above results. Quenching from high temperature showed the presence of lath-like features which were poor in Ta and Cr and had the B2 structure. Finally some regions with an orthorhombic structure were observed in the as quenched samples. Overall, peak hardness was obtained after aging the quenched Beta phase sample at 650 degrees C. This corresponded to a macrostructure of retained beta with a fine acicular structure of a2..
Mohamed, Hasan Daw Ashtawi. "DNA-based routes to metal, inorganic and polymer nanowires." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2150.
Повний текст джерелаTao, Ran. "Piezoelectric generators based on semiconducting nanowires : simulation and experiments." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT094/document.
Повний текст джерелаEnergy autonomy in small sensors networks is one of the key quality parameter for end-users. It’s even critical when addressing applications in structures health monitoring (avionics, machines, building…), or in medical or environmental monitoring applications. Piezoelectric materials make it possible to exploit the otherwise wasted mechanical energy which is abundant in our environment (e. g. from vibrations, deformations related to movements or air fluxes). Thus, they can contribute to the energy autonomy of those small sensors. In the form of nanowires (NWs), piezoelectric materials offer a high sensibility allowing very small mechanical deformations to be exploited. They are also easy to integrate, even on flexible substrates.In this PhD thesis, we studied the potential of semiconducting piezoelectric NWs, of ZnO or III-V compounds, for the conversion from mechanical to electrical energy. An increasing number of publications have recently bloomed about these nanostructures and promising nanogenerators (NGs) have been reported. However, many questions are still open with, for instance, contradictions that remain between theoretical predictions and experimental observations.Our objective is to better understand the physical mechanisms which rule the piezoelectric response of semiconducting NWs and of the associated NGs. The experimental work was based on the fabrication of VING (Vertical Integrated Nano Generators) devices and their characterization. An electromechanical characterization set-up was built to evaluate the performance and thermal effects of the fabricated NGs under controlled compressive forces. Atomic Force Microscopy (AFM) was also used to evaluate the Young modulus and the effective piezoelectric coefficients of GaN, GaAs and ZnO NWs, as well as of ZnO-based core/shell NWs. Among them, ZnO NWs were grown using chemical bath deposition over rigid (Si) or flexible (stainless steel) substrates and further integrated to build VING piezoelectric generators. The VING design was based on simulations which neglected the effect of free carriers, as done in most publications to date. This theoretical work was further improved by considering the complete coupling between mechanical, piezoelectric and semiconducting effects, including free carriers. By taking into account the surface Fermi level pinning, we were able to reconcile theoretical and experimental observations. In particular, we propose an explanation to the fact that size effects are experimentally observed for NWs with diameters 10 times higher than expected from ab-initio simulations, or the fact that VING response is non-symmetrical according to whether the substrate on which it is integrated is actuated with a convex or concave bending
Ebenhoch, Carola [Verfasser]. "Memristive Systems Based on Metal Oxide Nanowires / Carola Ebenhoch." Konstanz : KOPS Universität Konstanz, 2021. http://d-nb.info/1237222109/34.
Повний текст джерелаWang, Lixin. "Ferrocene-based molecular electronics and nanomanufacturing of palladium nanowires." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/7757.
Повний текст джерелаThesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Cano-Castillo, U. "Environment-assisted cracking of spray-formed Al-alloy and Al-alloy-based composite." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260730.
Повний текст джерелаKockert, Maximilian Emil [Verfasser]. "Thermoelectric transport properties of thin metallic films, nanowires and novel Bi-based core/shell nanowires / Maximilian Emil Kockert." Berlin : Humboldt-Universität zu Berlin, 2021. http://d-nb.info/123689698X/34.
Повний текст джерелаButt, M. Taqi Zahid. "Study of gold-based alloy phase diagrams." Thesis, Brunel University, 1990. http://bura.brunel.ac.uk/handle/2438/7389.
Повний текст джерелаSinghal, Dhruv. "Forêt de nanofils semiconducteurs pour la thermoélectricité." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY016/document.
Повний текст джерелаThermoelectric conversion has gained renewed interest based on the possibilities of increasing the efficiencies while exploiting the size effects. For instance, nanowires theoretically show increased power factors along with reduced phonon transport owing to confinement and/or size effects. In this context, the diameter of the nanowires becomes a crucial parameter to address in order to obtain high thermoelectric efficiencies. A usual approach is directed towards reducing the phononic thermal conductivity in nanowires by achieving enhanced boundary scattering while reducing diameters.In this work, thermal characterisation of a dense forest of silicon, germanium, silicon-germanium and Bi2Te3 alloy nanowires is done through a sensitive 3ω method. These forest of nanowires for silicon, germanium and silicon-germanium alloy were grown through bottom-up technique following the Vapour-Liquid-Solid mechanism in Chemical vapour deposition. The template-assisted and gold catalyst growth of nanowires with controlled diameters was achieved with the aid of tuneable nanoporous alumina as templates. The nanowires are grown following the internal geometry of the nanopores, in such a case the surface profile of the nanowires can be modified according to the fabricated geometry of nanopores. Benefiting from this fact, high-density growth of diameter-modulated nanowires was also demonstrated, where the amplitude and the period of modulation can be easily tuned during the fabrication of the templates. Even while modulating the diameters during growth, the nanowires were structurally characterised to be monocrystalline through transmission electron microscopy and X-ray diffraction analysis.The thermal characterisation of these nanowires revealed a strong diameter dependent decrease in the thermal conductivity, where the reduction was predominantly linked to strong boundary scattering. The mean free path contribution to the thermal conductivity observed in the bulk of fabricated nanowire materials vary a lot, where Bi2Te3 has strikingly low mean free path distribution (0.1 nm to 15 nm) as compared to the other materials. Even then, reduced thermal conductivities (~40%) were observed in these alloys attributed to boundary and impurity scattering. On the other hand, silicon and germanium have higher thermal conductivity with a larger mean free path distribution. In these nanowires, a significant reduction (10-15 times) was observed with a strong dependence on the size of the nanowires.While size effects reduce the thermal conductivity by enhanced boundary scattering, doping these nanowires can incorporate mass-difference scattering at atomic length scales. The temperature dependence of thermal conductivity was determined for doped nanowires of silicon to observe a reduction in thermal conductivity to a value of 4.6 W.m-1K-1 in highly n-doped silicon nanowires with 38 nm diameter. Taking into account the electrical conductivity and calculated Seebeck coefficient, a ZT of 0.5 was observed. With these significant increase in the efficiency of silicon as a thermoelectric material, a real practical application to devices is not far from reality
De, luna bugallo Andres. "Fabrication and characterization of nanodevices based on III-V nanowires." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00731763.
Повний текст джерелаTambe, Michael Joseph. "Controlled growth and doping of core-shell GaAs-based nanowires." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59237.
Повний текст джерелаIncludes bibliographical references (p. 151-158).
The use of compound semiconductor heterostructures to create electron confinement has enabled the highest frequency and lowest noise semiconductor electronics in existence. Modem technology uses two-dimensional electron gasses and there is considerable interest to explore one-dimensional electron confinement. This thesis develops the materials science toolkit needed to fabricate, characterize, and control the compositional, structural and electronic properties of core-shell GaAs/AlGaAs nanowires towards studying quasi-one-dimensional confinement and developing high mobility electronics First, nanowire growth kinetics were studied to optimize nanowire morphology. Variations in nanowire diameter were eliminated by understanding the role Ga adatom diffusion on sidewall deposition and vertical growth was enabled by understanding the importance of Ga and As mass-transport to nanowire nucleation. These results demonstrate that arrays of vertically-aligned GaAs nanowires can be produced. Then, the deposition of epitaxial AlGaAs shells on GaAs nanowires was demonstrated. By reducing the nanowire aerial density the stability of the nanowire geometry was maintained. A variety of analytical electron microscopy techniques confirmed the shell deposition to be uniform, epitaxial, defect-free, and nearly atomic sharp. These results demonstrate that core-shell nanowires possess a core-shell interface free of many of the imperfections that lithographically-defined nanowires possess. Finally, the adverse effect of the Au seed nanoparticle during n-type doping was identified and n-type doping was achieved via the removal of the Au nanoparticle prior to doping. A combination of energy dispersive X-ray spectroscopy, current-voltage, capacitance-voltage, and Kelvin probe force microscopy demonstrated that if the Au seed nanoparticle is present during the shell deposition, Au diffuses from the seed nanoparticle and creates a rectifying IV behavior. A process was presented to remove the Au nanoparticle prior to shell deposition and was shown to produce uniform n-type doping. The conductivity of GaAs/n-GaAs nanowires was calculated as a function of donor concentration and geometric factors taking into account the effects of Fermi level pinning. The control demonstrated over all of these parameters is sufficient enough for core-shell nanowires to be considered candidates for high mobility electronics.
by Michael Joseph Tambe.
Ph.D.
Luna, bugallo Andrès de. "Fabrication and characterization of nanodevices based on III-V nanowires." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112117/document.
Повний текст джерелаSemiconductor nanowires are nanostructures with lengths up to few microns and small cross sections (10ths of nanometers). In the recent years the development in the field of III-N nanowire technology has been spectacular. In particular they are consider as promising building in nanoscale electronics and optoelectronics devices; such as photodetectors, transistors, biosensors, light source, solar cells, etc. In this work, we present fabrication and the characterization of photodetector and light emitter based devices on III-N nanowires. First we present a study of a visible blind photodetector based on p-i-n GaN nanowires ensembles grown on Si (111). We show that these devices exhibit a high responsivity exceeding that of thin film counterparts. We also demonstrate UV photodetectors based on single nanowires containing GaN/AlN multi-axial quantum discs in the intrinsic region of the nanowires. Photoluminescence and cathodoluminescence spectroscopy show spectral contributions above and below the GaN bandgap according to the variation of the discs thickness. The photocurrent spectra show a sub-band-gap peak related to the interband absorption between the confined states in the large Qdiscs. Finally we present a study of photodetectors and light emitters based on radial InGaN/GaN MQW embedded in GaN wires. The wires used as photodetectors showed a contribution below the GaN bandgap. OBIC measurements demonstrate that, this signal is exclusively generated in the InGaN MQW region. We showed that LEDs based on this structure show a electroluminescence emission and a red shift when the In content present in the QWs increases which is in good agreement with photoluminescence and cathodoluminescence results
Lari, Leonardo. "Investigation of growth and structure of gallium nitride based nanowires." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507165.
Повний текст джерелаAbdullah, Ilyaas. "CdSe based nanowires for the photocatalytic production of hydrogen gas." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29398.
Повний текст джерелаHull, S. "Precipitation in aluminium based and iron based alloys." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370120.
Повний текст джерелаSquire, Peter James. "Development of multi-component iron-based amorphous alloy." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/462/.
Повний текст джерелаLei, Wang S. "Potential applications of a toughened silicon-based alloy." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45385.
Повний текст джерелаIncludes bibliographical references (leaves 21-22).
Silicon has long been used as an alloying element in various metal alloys, in engineered ceramics, and in the semiconductor industry. However, due to its intrinsic low fracture toughness, it is generally perceived as a poor choice of material for mechanical applications. This study explores some potential short and long term applications for a new type of castable silicon-rich alloy with an increased fracture toughness, by utilizing several different material selection indices.
by Wang S. Lei.
M.Eng.
Ching, Suet Ying. "Plasmonic properties of silver-based alloy thin films." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/194.
Повний текст джерелаGorsky, Daniel A. "Niyama Based Taper Optimizations in Steel Alloy Castings." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1316191746.
Повний текст джерелаBöhnert, Tim [Verfasser], and Kornelius [Akademischer Betreuer] Nielsch. "Magneto-thermopower and Magnetoresistance of Co-Ni Alloy and Co-Ni/Cu Multilayered Nanowires. / Tim Böhnert. Betreuer: Kornelius Nielsch." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2014. http://d-nb.info/1052996698/34.
Повний текст джерелаOffenberger, Sean Alan. "Investigation of Zinc Oxide Nanowires for Impedance Based Structural Health Monitoring." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82502.
Повний текст джерелаMaster of Science
Roussey, Arthur. "Preparation of Copper-based catalysts for the synthesis of Silicon nanowires." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10164.
Повний текст джерелаThe work presented in this PhD thesis aimed at the preparation of copper nanoparticles of controllable size and their utilization as catalysts for the growth of silicon nanowires in a process compatible with standard CMOS technology and at low temperature (< 450°C). The growth of silicon nanowires by Chemical Vapor Deposition (CVD) via the catalytic decomposition of a silicon precursor on metallic nanoparticles at low temperature (Vapor Solid-Solid process) was demonstrated to be possible from an oxidized Cu thin film. However, this process does not allow the control over nanowires diameter, which is controlled by the diameter of the nanoparticle of catalyst. In this PhD is presented a fully bottom-up approach to prepare copper nanoparticles of controllable size directly on a surface without the help of external stabilizer by mean of surface organometallic chemistry. First, the preparation of copper nanoparticles is demonstrated on 3D substrates (silica and titanium nitride nanoparticles), along with the fine comprehension of the formation mechanism of the nanoparticles as a function of the surface properties. Then, this methodology is transferred to planar (2D) substrates typically used in microelectronics (silicon wafers). Surface structure is demonstrated to direct the Cu nanoparticles diameter between 3 to 40 nm. The similarities between the 2D and 3D substrates are discussed. Finally, the activity of the Copper nanoparticles in the growth of Silicon nanowire is presented and it is demonstrated that in our conditions a critical diameter may exist above which the growth occurs
REZVANI, SEYED JAVAD. "Fabrication and characterization of semiconductor Nanowires based on Silicon and Germanium." Doctoral thesis, Università degli Studi di Camerino, 2014. http://hdl.handle.net/11581/401771.
Повний текст джерелаDong, Zhenning. "Synthesis of GaAs nanowires and nanostructures by HVPE on Si substrate. Application to a microbial fuel cell based on GaAs nanowires." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC091/document.
Повний текст джерелаIII-V semiconductor nanowires exhibit excellent electrical and optical properties in laterally confined geometry which is very promising for monolithic integration of photonic nanodevices on silicon substrates. Hydride Vapor Phase Epitaxy (HVPE) process growth was therefore developed in this thesis for the growth of GaAs nanowires. This report is organized into two chapters.The first chapter introduces the state-of-the-art of self-catalyzed GaAs nanowires and nano-structures on silicon substrate. We have demonstrated the growth of self - catalyzed GaAs nanowires by HVPE on un-patterned Si (111) substrates at a low temperature of 600 °C with extremely high GaCl/AsH3 flow ratios. A model that explains well the experimental findings was developed. The second part proposes the design of a Microbial Fuel Cell (MFC) prototype based on GaAs nanowire samples. A MFC prototype based on GaAs nanowire and substrate was developed
Li, Suiqiong. "Development of novel acoustic wave biosensor platforms based on magnetostriction and fabrication of magnetostrictive nanowires." Auburn, Ala., 2007. http://repo.lib.auburn.edu/07M%20Dissertations/LI_SUIQIONG_40.pdf.
Повний текст джерелаMallampati, Bhargav. "Development of High Gain Ultraviolet Photo Detectors Based on Zinc Oxide Nanowires." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500106/.
Повний текст джерелаHuang, Aijun. "Alloy and process development in cast TiAl-based materials." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433490.
Повний текст джерелаMazwi, Sive. "Hydrogen storage in Ti-based coatings and Ti6Al4V alloy." University of the Western Cape, 2016. http://hdl.handle.net/11394/5319.
Повний текст джерелаHydrogen has been regarded as an ideal energy carrier for future, it can be stored as a liquid in cryogenic tanks, a gas in high pressure cylinders and as solid in metal hydrides. Hydrogen storage in metal hydrides is of research interest because hydrides often have high energy density than gas or liquid hydrogen and are relatively safe. Ti and Ti alloys are promising hydrogen storage material because they have high affinity for hydrogen, light in weight and react reversibly with hydrogen. This work aims to investigate the hydrogen storage capacity of CP- Ti and Ti6Al4V alloy and Pd/Ti6Al4V alloy, where Pd was deposited on Ti6Al4V alloy. Samples were hydrogenated from room temperature to 650 °C at atmospheric pressure in the vacuum furnace under the 15%H/Ar atmosphere. Hydrogenation was carried out for a period of 3 hours for all samples. Sample composition and layer thickness were determined using Rutherford backscattering spectrometry. The microstructure and phase transformation were investigated using optical microscopy and X-ray diffraction technique. Hydrogen storage capacity was determined using elastic recoil detection analysis and gravimetric method. It was found that hydrogenation temperature has an effect on hydrogen absorption, microstructure and phase transformation. Maximum hydrogen concentration was obtained at hydrogenation temperatures of 550 °C for all materials with 45.57 at.% in CP-Ti, 34.77 at.% in Ti6Al4V alloy and 39 at.% H in Pd/Ti6Al4V coated system. In CP-Ti it was found that hydrogen absorption begins at 550 °C and decreases at hydrogenation temperature of 650 °C and that hydrogenation at both temperatures leads to formation of titanium hydrides and needlelike microstructure. At temperatures below 550 °C no hydrides were formed. For Ti6Al4V alloy ERDA results showed that no significant hydrogen absorption occurred at temperatures below 550 °C and at hydrogenation temperature of 650 °C, hydrogen absorption decreased drastically. The δ- titanium hydride was detected in the sample hydrogenated at 550 °C. Fine needle like microstructure was observed in the sample hydrogenated at 550 °C, and at higher temperature (650 °C ) coarse needles were formed. Pd coatings on Ti6Al4V alloy was found to increase the absorption of hydrogen, and allowing hydrogen to be absorbed at low temperatures.
National Research Foundation (NRF)
Ahmed, Rizwan, and Shahid Abbas. "Electrical and Optical Characteristics of InP Nanowires based p-i-n Photodetectors." Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-13915.
Повний текст джерелаTanaka, Hajime. "Theoretical Study on Carrier Transport in Semiconductor Nanowires Based on Atomistic Modeling." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225606.
Повний текст джерелаMusolino, Mattia. "Growth, fabrication, and investigation of light-emitting diodes based on GaN nanowires." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17409.
Повний текст джерелаThis PhD thesis provides an in-depth insight on various crucial aspects of light-emitting diodes (LEDs) based on (In,Ga)N/GaN heterostructures grown along the axis of nanowires (NWs) by molecular beam epitaxy on Si substrates. In particular, the growth parameters are adjusted so as to suppress the coalescence of NWs; in this way the photoluminescence (PL) intensity emitted from the NW-LEDs can be increased by about ten times. The opto-electronic properties of the NW-LEDs can be further improved by exclusively employing indium tin oxide instead of Ni/Au as top contact. Furthermore, the compatibility of selective-area growth (SAG) of GaN NWs on AlN-buffered Si substrates with device operation is demonstrated, thus paving the way for a new generation of LEDs based on homogeneous NW ensembles on Si. Ordered arrays of ultrathin NWs are also successfully obtained by combining SAG and in situ post-growth thermal decomposition. A double-line structure is observed in the electroluminescence (EL) spectra emitted by the NW-LEDs; it is likely caused by compressive strain introduced by the (Al,Ga)N electron blocking layer in the neighbouring (In,Ga)N quantum well. An in-depth analysis of temperature dependent PL and EL measurements indicates that carrier localization phenomena do not dominate the EL emission properties of the NW-LEDs. The forward bias current-voltage (I-V) characteristics of different NW-LEDs are analysed by means of an original model that takes into account the multi-element nature of LEDs based on NW ensembles by assuming a linear dependence of the ideality factor on applied bias. The transport mechanisms in reverse bias regime are carefully studied by means of deep level transient spectroscopy (DLTS) and temperature dependent I-V measurements. The physical origin of the detected deep states is discussed. Then, a physical model able to describe quantitatively the peculiar I-V-T characteristics of NW-LEDs is developed.
Chatterjee, Dipanwita. "Insights into Nucleation, Growth and Shape Control for Designing Anisotropic Nanostructures and Heterostructures." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/5357.
Повний текст джерелаLee, Soohwan. "First principles-based atomistic modeling of the structure and nature of amorphous Au-Si alloys and their application to Si nanowire synthesis." 2008. http://hdl.handle.net/2152/18244.
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Burr, Loïc. "Ion-track technology based synthesis and characterization of gold and gold alloys nanowires and nanocones." Phd thesis, 2016. https://tuprints.ulb.tu-darmstadt.de/5541/1/Thesis-Lo%C3%AFc-Burr-e-print.pdf.
Повний текст джерелаPhillips, Francis Randall. "Fabrication and Characterization of Nanowires." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8355.
Повний текст джерелаZhen-BangTey and 鄭振邦. "The Preparation and Applications of Magnetic Alloy Nanowires." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/85586135939471703247.
Повний текст джерела國立成功大學
化學工程學系碩博士班
101
One-dimensional magnetic materials with large magnetic anisotropy have been intensively studied. Its unique high aspect ratio characteristic has been widely used in various fields. Many methods including template-assisted growth, magnetic-field assisted hydrothermal, solvothermal synthesis and electrospinning have been developed to design and fabricate 1D magnetic nanostructures, but these methods usually suffer from tedious procedures, high temperature, high pressure, long reaction and templates. In this study, we demonstrate a magnetic-field induced wet chemical reduction method which is rapid and inexpensive approach to fabricate 1D magnetic materials at room temperature with a fast reaction rate and a high yield. In order to improve the magnetic properties of 1D materials, first, we use nickel chloride and cobalt acetate as the metal salt precursor to fabricate Ni-Co alloy nanowires. The magnetic properties were studied by superconducting quantum interference device (SQUID). The saturation magnetization (Ms) increases by increasing the mole fraction of cobalt. The saturation magnetization of pure Ni nanowires were determined to be about 60.52emu/g, while Ni9Co1, Ni8Co2 and Ni7Co3 alloy nanowire samples were determined to be about 74.47, 90.4, 112.59emu/g, respectively. Ni-Fe alloy nanowires were also fabricated using the similar method. The values of saturation magnetization of Ni9Fe1 and Ni8Fe2 alloy nanowire samples were determined to be about 81.24 and 112.76emu/g, which are higher than the pure Ni nanowires. Since the magnetic properties of cobalt are relatively higher than nickel, we attempt to fabricate the cobalt nanowires. The particle structure can be observed when the ratio of the Ni-Co was up to 6:4 in the system, where water was used as the solvent, and sodium citrate as the dispersant. Cobalt flower-like structure can be also observed when the ratio Ni:Co=0:10. However, changing the solvent to ethylene glycol can prevent the occurrence of the flower-like structure significantly and the Ni, Ni7Co3, Ni5Co5, Ni3Co7 and Co nanowires were fabricated successfully. The saturation magnetization of the 1D cobalt wire were determined to be about 176emu/g which is higher than the 0D cobalt sphere (160emu/g). In this work, we also used the similar method to fabricate Ni-Pt, Ni-Pd nanowires in the different ratios of 9:1, 8:2, 7:3 and 6:4. The degree of alloy becomes more obvious by increasing the composition of Pt or Pd. The diffraction angle also changed approximately with the linear function to the composition of Pt or Pd. Furthermore, Ag dendrites were successfully grown on the chelated copolymer template. The complete dendrites were grown under the PVP concentration of 0.1μM. Moreover, the membrane with Ag dendrites was used as Surface-enhanced Raman Spectroscopy (SERS) substrate and the characteristic peaks of R6G were successfully enhanced in the spectrum.
Li, Zhong. "Growth and Characterization of ZnSe and ZnTe Alloy Nanowires." Thesis, 2012. http://hdl.handle.net/1807/33854.
Повний текст джерелаHu, Chen-Yu, and 胡宸瑜. "Growth and Analysis of AuMn Alloy-Catalyzed Si Nanowires." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/udt6hp.
Повний текст джерела國立臺灣大學
材料科學與工程學研究所
105
Because of the transport property of semiconductors and the ability to control the electron spin, diluted magnetic semiconductor nanowires have good potential in spintronic applications. The confinement effect in the nanowire structure also improves the spin relaxation in the spintronic devices. In addition, manganese can provide large magnetic moment in silicon, Mn-doped Si nanowires is therefore an ideal candidate for spintronic devices. However, the low solubility of manganese in silicon making it very difficult to fabricate manganese-doped silicon nanowires. In this study, the process window of growing Si nanowire using AuMn and pure Mn catalysts via the vapor-liquid-solid mechanism (VLS) in a chemical vapor deposition (CVD) reactor is firstly investigated. Analyses on the resulted structure and composition distribution and the effects from the growth substrates are discussed. The Ge sites in SiGe nanowires helps the incorporation of Mn in the nanowires. Thus, the second part of this study focuses on the incorporation of Mn into SiGe nanowires through oxidizing the as-grown AuMn/SiGe nanowires to form a SiGe section with a higher Ge content. The morphology change of the nanowire due to the oxidation process and the change of chemical distribution is discussed.
Zhang, Xi Dickey Elizabeth C. "Size effects in alloy and heterostructured Si₁-x[subscript]Gex[subscript] nanowires." 2009. http://etda.libraries.psu.edu/theses/approved/PSUonlyIndex/ETD-4198/index.html.
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