Dissertations / Theses on the topic 'Coulomb blockade'
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Kubala, Björn. "Quantentransport durch Coulomb-Blockade-Systeme." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982839146.
Full textAli, Danish. "Coulomb blockade in silicon-on-insulator." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321368.
Full textPetej, Ivan. "Coulomb blockade and quantum conductance in ferromagnetic nanostructures." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270647.
Full textWilson, Dominic Simon. "Scanning tunnelling spectroscopy of superconductors and Coulomb blockade effects." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264499.
Full textDovinos, Dimitris. "Charge transport in a Coulomb blockade island under irradiation." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619516.
Full textJohansson, Jan. "Single Charge and Spin Transport in Nanostructures." Doctoral thesis, KTH, Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3685.
Full textPaul, Douglas John. "Single electronics in #delta#-doped silicon germanium." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321519.
Full textAndersson, Karin. "Coulomb blockade of Cooper pair tunneling in one dimensional Josephson junction arrays." Doctoral thesis, KTH, Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3393.
Full textStegmann, Philipp [Verfasser], and Jürgen [Akademischer Betreuer] König. "Generalized factorial cumulants applied to Coulomb-blockade systems / Philipp Stegmann ; Betreuer: Jürgen König." Duisburg, 2017. http://d-nb.info/1136863990/34.
Full textFühner, Claus. "Magneto-transport investigations on multi-electron quantum dots Coulomb blockade, Kondo effect and Fano regime /." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967772753.
Full textBhandari, Nikhil K. "Tunable All Electric Spin Polarizer." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1393237571.
Full textMartinez, Rivas Adrian. "Wafer scale integration of coulomb blockade-based nanobiosensors with microfluidic channels for label-free detection of cancer biomarkers." Toulouse, INSA, 2009. http://eprint.insa-toulouse.fr/archive/00000344/.
Full textDans cette thèse, nous proposons et démontrons un nouveau type de nanobiocapteur pour la détection de biomolécules à haute sensibilité et leur intégration à grande échelle (plaquette de 4 pouces). Le principe du nouveau nanobiocapteur électrique est basé sur la variation de conductivité électrique à travers des nano-îlots grâce au phénomène quantique appelé « blocage de Coulomb ». Les nano-îlots de nickel (~5nm de diamètre) sont placés entre les nano-électrodes interdigitées (IND) (~45nm de largeur). La conductivité de ces dispositifs à Jonctions Tunnel Multiples (MTJ) est modifiée par l’adsorption de biomarqueurs impliqués dans la tumorogènese. Les oncologues ont récemment isolé et caractérisé un nouveau fragment d’anticorps à chaîne simple (scFv) qui reconnaît sélectivement la forme active de RhoA. Ce biomarqueur potentiel a été trouvé surexprimé dans diverses tumeurs. Les fragments d’anticorps ont été adsorbés, par des liaisons de coordination, sur les nano-îlots de nickel. Ces fragments sont capables de reconnaître spécifiquement la forme active de RhoA. Nous avons étudié ce biomarqueur et validé la chimie de surface à base de nano-’îlots de nickel pour la détection sans marquage, en utilisant une microbalance à quartz (QCM). Puis, nous avons mis au point et adapté à notre dispositif une méthodologie innovatrice pour réaliser, à l’échelle d’une plaquette, des microcanaux basés sur du photoPDMS. La caractérisation électrique finale des dispositifs intégrés a été testée en temps réel et à flux biologique continu. La forme active de RhoA a été détectée en discriminant la forme inactive. En annexe, je présente mon opinion épistémologique et éthique sur la nanotechnologie
Godel, Florian. "Le graphène comme barrière tunnel : propriétés d'injection de charges et de spin." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE029/document.
Full textMy PhD thesis deals with the fabrication and the electric and magnetic characterizations of magnetic tunnel junctions based on graphene. The interaction of graphene with its close environment opens new possibilities for spintronics applications. The manuscript is focused on the improvement of the understanding of mechanisms involved in the injection and detection of a polarized spin current at the graphene/ferromagnetic interfaces. We show that it is possible to grow epitaxially MgO tunnel barrier on graphene. We study the spin transport mechanisms in vertical junctions of Co/MgO/Gr/Ni. The interaction of graphene with nickel electrode is probed through tunnel magnetoresistance inversions which can be explained by the activation of phonon assisted conduction channel. We also measure in vertical and lateral devices based on alumina barrier on graphene, reproducible Coulomb blockade processes linked to the presence of monodisperse aluminum clusters at the graphene edge
Wang, Hongyue. "On-chip tunneling spectroscopy of colloidal quantum dots." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066555/document.
Full textMy PhD work consists in a study of single Quantum Dot (QD) tunnel junctions. Following the introduction chapter, the second chapter will present the fundamental concepts needed to describe a single QD junction, such as quantum confinement and Coulomb blockade. In the third chapter, I will describe the sample fabrication methods and the measurement setups. In the fourth chapter, I will describe a tunneling spectroscopy study of single PbS QDs. Three distinct signatures of strong electron-phonon coupling are observed in the Electron Tunneling Spectrum (ETS) of these QDs. In the shell-filling regime, the 8 times degeneracy of the electronic levels is lifted by the Coulomb interactions and allows the observation of phonon sub-bands that result from the emission of optical phonons. At low bias, a gap is observed in the spectrum that cannot be closed with the gate voltage, which is a distinguishing feature of the Franck-Condon blockade. From the data, a Huang-Rhys factor in the range S~ 1.7 - 2.5 is obtained. Finally, in the shell tunneling regime, the optical phonons appear in the inelastic ETS d2I/dV2. In the fifth chapter, I present a tunnel spectroscopy study of single HgSe QDs. Upon tuning the gate voltage, different occupation levels of the QD can be reached. The gap observed in the ETS changes with the occupation level. A large inter-band gap, 0.9~eV, is observed for the empty QDs, and an intra-band gap 0.2~eV is observed for the doubly occupied QD. Upon illuminating the QD, a photocurrent can be measured using an especially designed demodulation technique. From this measurement, the lifetime τ ~65 μs is extracted for the photogenerated electron-hole in the QD
Liu, Tai-Min. "Electronic Interactions in Semiconductor Quantum Dots and Quantum Point Contacts." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1311773375.
Full textDirnaichner, Alois Roman [Verfasser], C. [Akademischer Betreuer] Strunk, and M. [Akademischer Betreuer] Grifoni. "Charge and spin transport in carbon nanotubes: From Coulomb blockade to Fabry-Perot interference / Alois Roman Dirnaichner ; C. Strunk, M. Grifoni." Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1122825188/34.
Full textWang, Hongyue. "On-chip tunneling spectroscopy of colloidal quantum dots." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066555.
Full textMy PhD work consists in a study of single Quantum Dot (QD) tunnel junctions. Following the introduction chapter, the second chapter will present the fundamental concepts needed to describe a single QD junction, such as quantum confinement and Coulomb blockade. In the third chapter, I will describe the sample fabrication methods and the measurement setups. In the fourth chapter, I will describe a tunneling spectroscopy study of single PbS QDs. Three distinct signatures of strong electron-phonon coupling are observed in the Electron Tunneling Spectrum (ETS) of these QDs. In the shell-filling regime, the 8 times degeneracy of the electronic levels is lifted by the Coulomb interactions and allows the observation of phonon sub-bands that result from the emission of optical phonons. At low bias, a gap is observed in the spectrum that cannot be closed with the gate voltage, which is a distinguishing feature of the Franck-Condon blockade. From the data, a Huang-Rhys factor in the range S~ 1.7 - 2.5 is obtained. Finally, in the shell tunneling regime, the optical phonons appear in the inelastic ETS d2I/dV2. In the fifth chapter, I present a tunnel spectroscopy study of single HgSe QDs. Upon tuning the gate voltage, different occupation levels of the QD can be reached. The gap observed in the ETS changes with the occupation level. A large inter-band gap, 0.9~eV, is observed for the empty QDs, and an intra-band gap 0.2~eV is observed for the doubly occupied QD. Upon illuminating the QD, a photocurrent can be measured using an especially designed demodulation technique. From this measurement, the lifetime τ ~65 μs is extracted for the photogenerated electron-hole in the QD
MEHDY, MALIK ASHTER. "Simulation and Modeling of Silicon Based Emerging Nanodevices: From Device to Circuit Level." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2711314.
Full textAghili, Yajadda Mir Massoud. "An investigation on the electrical and optical properties of thin films of gold nanoislands." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/18963.
Full textMüller, Jonas. "Finite frequency dynamics in correlated quantum conductors." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASP061.
Full textIn this work, we present the new experimental methods that we have developed in order to investigate the fundamental physics of electronic transport across mesoscopic conductors based on the measurement of electrical fluctuations. In the first part of the thesis we present a novel design of a back-action free quantum detector to separately measure the power spectral density of current fluctuations for positive (absorption noise) and negative (emission noise) frequencies. We extract the absorption and emission noise from a measurement of the power exchanged between a quantum conductor and a finite frequency linear resonator, tested for a SIS junction coupled to a cavity filter. Our results stress the physical meaning of the Kubo formula which, coupled to a quantum description of the measurement setup, provides a quantum version of Joule’s theorem. In the second part of the thesis, we present the design and construction of an experimental platform for time dependant RF-measurements in high magnetic fields. The goal is to efficiently measure a quantum conductor that gives rise to a detection back-action on its transport properties, known as Dynamical Coulomb Blockade (DCB). We wish to investigate such effects in the elementary case of a single conduction channel, with arbitrary transmission, interacting with a single electromagnetic mode. The main challenge is the engineering of high impedance RF resonators used as impedance transformer to efficiently couple the high impedance single channel (25.8 kΩ) to the mismatched 50 Ω RF-detection equipment. For our setup we have firstly designed and tested a magnetic field tolerant resonator, a planar metallic coil, that provides a characteristic impedance of 1 kΩ at a resonance frequency of 5.4 GHz. Using two resonators in series, an effective detection impedance of 27 kΩ is achievable that provides sufficient coupling to a single channel. With all the methodologies developed in this thesis, it is now possible to perform an amazing series of various experiments in the near future
Fairbanks, Matthew Stetson 1981. "Electron transport in micro to nanoscale solid state networks." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/10585.
Full textThis dissertation focuses on low-dimensional electron transport phenomena in devices ranging from semiconductor electron 'billiards' to semimetal atomic clusters to gold nanoparticles. In each material system, the goal of this research is to understand how carrier transport occurs when many elements act in concert. In the semiconductor electron billiards, magnetoconductance fluctuations, the result of electron quantum interference within the device, are used as a probe of electron transport through arrays of one, two, and three connected billiards. By combining two established analysis techniques, this research demonstrates a novel method for determining the quantum energy level spacing in each of the arrays. That information in turn shows the extent (and limits) of the phase-coherent electron wavefunction in each of the devices. The use of the following two material systems, the semimetal atomic clusters and the gold nanoparticles, is inspired by the electron billiard results. First, the output of the simple, rectangular electron billiards, the magnetoconductance fluctuations, is quite generally found to be fractal. This research addresses the question of what output one might expect from a device with manifestly fractal geometry by simulating the electrical response of fractal resistor networks and by outlining a method to implement such devices in fractal aggregates of semimetal atomic clusters. Second, in gold nanoparticle arrays, the number of array elements can increase by orders of magnitude over the billiard arrays, all with the potential to stay in a similar, phase-coherent transport regime. The last portion of this dissertation details the fabrication of these nanoparticle-based devices and their electrical characteristics, which exhibit strong evidence for electron transport in the Coulomb-blockade regime. A sketch for further 'off-blockade' experiments to realize magnetoconductance fluctuations, i.e. phase-coherent electron phenomena, is presented.
Committee in charge: Jens Noeckel, Chairperson, Physics; Richard Taylor, Member, Physics; Heiner Linke, Member, Physics; David Strom, Member, Physics; James Hutchison, Outside Member, Chemistry
ENRICO, EMANUELE. "Fabrication and characterization of hybrid single electron devices." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2502235.
Full textUsmani, Suhail. "Charge transport in the assemblies of magnetic, non-magnetic and spin-cross over nano-structures." Thesis, Toulouse, INSA, 2018. http://www.theses.fr/2018ISAT0012.
Full textUnderstanding charge transport properties of metallic and magnetic nano-structures is highly important for the development and miniaturization of modern functional devices. In particular, chemically synthesized nano-structures are in focus as they provide better control over their shape and size, which can be used to tune their charge transport properties. The aim of this thesis is to study the various aspects of charge transport properties which emerge due to the small size and magnetic nature of different types of nanostructures which include Pt nanoparticles (1.3-3 nm), FeCo magnetic particles (⁓10 nm), and Fe (II) triazole based coordination complex. To further specify, phenomenon such as Coulomb blockade, tunnel magnetoresistance and spin-transition will be in focus. Depending on the desirable property, these nanostructures can be exploited for their applications in a variety of sensors, actuators and spintronic devices etc
PASCUAL, GARCIA Cesar. "Low lying excitations of few electrons in quantum dots." Doctoral thesis, Scuola Normale Superiore, 2007. http://hdl.handle.net/11384/85855.
Full textJebari, Salha. "The inelastic Cooper pair tunneling amplifier (ICTA)." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY036/document.
Full textJosephson parametric amplifiers (JPA), have proven to be an indispensable tool for awide range of experiments on quantum devices in the microwave frequency regime, becausethey provide the lowest possible noise. However, JPAs remain much more difficult to use andoptimize than conventional microwave amplifiers. Recent experiments with superconductingcircuits consisting of a DC voltage-biased Josephson junction in series with a resonator,showed that a tunneling Cooper pair can emit one or several photons with a total energyof 2e times the applied voltage. In this thesis we show that such q circuit can be used toimplement a new type of phase preserving microwave amplifier, which we call InelasticCooper pair Tunneling Amplifier (ICTA). It is powered by a simple DC bias and offers nearquantum-limited noise performance.We start this work by presenting a brief and simple picture of the basic ICTA operatingprinciples. In analogy with the quantum theory of JPAs, we calculate the performances ofthis amplifier such as the gain, bandwidth and noise. Then, we present the first experimentalproof that amplification close to the quantum limit is possible without microwave drive inan extremely simple setup. These measurements are made on a first generation of samplesbased on aluminium junctions. According to our theoretical and experimental results, wehave designed microwave circuits presenting specific frequency-dependent impedances tothe junction in order to optimize the performances of our amplifier. This second generationof ICTA samples is fabricated from niobium nitride and provide significantly lower noiseand higher gain.We expect that once fully optimized, such an amplifier, powered by simple DC voltagescould then make measuring microwave signals at the single photon level much easier andallow to deploy many amplifiers on a chip. It could therefore be an important ingredient forqubit readout in large-scale quantum processors
Baines, David Yann. "Effet Kondo dans des boîtes quantiques couplées latéralement." Grenoble, 2010. http://www.theses.fr/2010GRENY063.
Full textThe Kondo effect arises when a single magnetic impurity is tunnel coupled to a Fermi sea. The essence of this highly correlated electron state is found in the non-perturbative nature of the exchange interaction between the local moment and the surrounding conduction electrons which leads to a non-magnetic ground state at zero temperature. In the Kondo regime all the physical quantities of the system (impurity + electron reservoir) scale with a unique energy being the Kondo temperature TK. This universal character has been observed in metals containing a large number of magnetic impurities and in manmade artificial magnets such as quantum dots. To be experimentally observable, the tunneling element connecting the local moment and the Fermi reservoir has to be large and the Kondo problem is often referred to as a strong coupling limit. Laterally defined quantum dots offer great possibilities to investigate further more the Kondo effect. In particular, constraining the Fermi sea to a finite region and studying how this influences the screening of the local moment appears to be a crucial question in the Kondo problem. We will present transport measurements through a double quantum dot where a small quantum dot acting as a magnetic impurity will be tunnel coupled to a large quantum dot being the finite size reservoir. Different experiments performed in the strong inter-dot coupling limit will confront us to the multi-level nature of the large quantum dot where hybridization of both objects has to be carried over several energy levels. Furthermore, we will present data where evidences of transport mechanisms through the system are mediated by a Kondo mechanism through a hybridized level of the dots. At the double dot charge degeneracy point, a boosting of the Kondo temperature due to the reduction of the charging energy of the system, enables to reveal a Kondo singlet at finite temperature. By considering the different spin configurations possible in our system, we will discuss the competition between two possible singlet states one can stabilize in the system, a Kondo type singlet and a inter-dot singlet where multi-level effects play an important role. We believe that the reduction of the exchange coupling between the two dots due to the small level spacing in the large dot explains the invariance of the phenomenon with respect to the occupation number of the large dot at our base electron temperature
Talbo, Vincent. "Étude théorique du transport électronique dans les nanodispositifs à boîtes quantiques semiconductrices." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00783430.
Full textJúnior, Vivaldo Leiria Campo. "Condução eletrônica através de um contato quântico pontual." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-15092008-110734/.
Full textIn this work a renormalization-group calculation of the low-temperature AC conductance in the linear response regime through a nanostructure coupled to metallic leads is presented. This system shows a competition between two effects: the Coulomb blockade and the Kon¬do effect. Our model considers one-dimensional leads which are connected to form a ring, in which a current is induced by a magnetic flux oscillating at the frequency . We start from a nearest-neighbor tight-binding model for the leads and in this way the potential vector is easily incorporated in the model Hamiltonian by twisting boundary conditions. A potential barrier between the leads and the nanostructure is simulated in terms of a tunneling rate between the nanostructure and the adjacent sites in the leads, which is smaller than the one between neighbors sites in the leads. The capacity of the nanostructure is small, which implies that substantial energy changes are associated with each electron transfered to the nanostructure. As a consequence, the model Hamiltonian maps onto the spin-degenerate Anderson Hamiltoni¬an with correlation U between the electrons. A gate voltage Vg controls the impurity (i.e., nanostructure) energy 0. Plotted as a function of , the conductivity shows two Coulomb-blockade peaks, at the energy needed to add an electron to and to remove an electron from the nanostructure, respectively. In the Kondo regime 0 > 0 > -U (i.e., for gate voltages such that the isolated nanostructure would have a spin-degeneration ground state), an addition (Kondo) peak appears near = 0. Plotted as functions of Vg, the static conductivity shows a broad peak in the Kondo regime and drops rapidly to zero for voltages resulting in a non-degenerate nanostructure ground state. A relation between the conductance and the spectral density of the impurity is obtained and used to interpret the numerical results.
Blancon, Jean-Christophe. "Optical absorption and electronic properties of individual carbon nanotubes." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10164/document.
Full textIn this dissertation, we report on the experimental investigation of the optical properties of single- and double-wall carbon nanotubes. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. In particular direct quantitative measurement of their absorption cross-section has not been achieved yet. Using spatial modulation spectroscopy we have determined, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of identified individual single- and double-wall carbon nanotubes. These quantitative measurements permit the determination of the oscillator strength of the different excitonic resonances. Furthermore, investigation of the same nanotube, either a single-wall or double-wall nanotube, freestanding or deposited on a substrate shows large broadening with increase of oscillator strength of the excitonic resonances, as well as stark weakening of polarization dependent antenna effects, due to nanotube-substrate interaction. Similar study on nanotube bundles and double-wall nanotubes demonstrate the importance of inter-tube and inter-wall exciton coupling effects which seem to be of different nature in these two types of sample. The second part of this thesis studies electrical transport in carbon nanotube bundles under high pressure condition and low temperature. The behavior of nanotubebased field-effect transistors has been investigated, in the classical and Coulomb blockade regime, under gas-pressure up to 0.9 GPa. Overall, this dissertation communicates on the quantitative analysis of the absorption and electronic properties of carbon nanotubes and how they are influenced by various environmental effects such as dielectric screening, stress induced strain, hydrostatic pressure, or chemical doping. The novelty of this work is to address these issues at the single nanotube level
Loubat, Anais. "Croissance par voie chimique et propriétés de transport électronique de nanofils d'or." Phd thesis, INSA de Toulouse, 2014. http://tel.archives-ouvertes.fr/tel-01037878.
Full textLarsson, Daniel Mikael. "Noise in coulomb blockaded quantum dots and kondo systems." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1535/.
Full textGöttel, Stefan [Verfasser], Herbert [Akademischer Betreuer] Schoeller, and Dirk [Akademischer Betreuer] Schuricht. "Renormalization group approaches to low dimensional systems : scrutinization of the spin functional RG for the 2D XXZ Model real time RG study of a generic 2-level quantum dot in the Coulomb blockade regime in nonequilibrium / Stefan Göttel ; Herbert Schoeller, Dirk Schuricht." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1128316579/34.
Full textDugay, Julien. "Intégration et mesures de magnéto-transport de nano-objets magnétiques obtenus par voie chimique." Phd thesis, INSA de Toulouse, 2012. http://tel.archives-ouvertes.fr/tel-00864511.
Full textDeshpande, Veeresh. "Scaling Beyond Moore: Single Electron Transistor and Single Atom Transistor Integration on CMOS." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00813508.
Full textNegri, Carlotta. "Controlling electron transport : quantum pumping and single-electron tunneling oscillations." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14670/document.
Full textExploiting time-dependent effects to induce and control currents through mesoscopic and nano\-scopic conductors is a major challenge in the field of quantum transport. In this dissertation we consider two nanoscale systems in which a current can be induced through intriguing mechanisms of coupling between excitations by external fields and electron transport.We first study a quantum pumping problem, analyzing the possibility to induce a DC response to an AC parametric driving through a three-site system in a ring configuration. We are interested in particular in the crossover between adiabatic and antiadiabatic driving regimes and in the presence of dissipation, which is accounted for by coupling with an external bath. We show that for a clever choice of this coupling the dissipative model admits a full analytical solution for the steady state current valid at arbitrary frequency, which allows us to fully understand the pumping-frequency dependence of the induced current. We then focus on a different current-controlling scheme exploiting the phenomenon of single-electron tunneling oscillations (SETOs). In this case, opposite to what happens for pumping, an AC effect, an almost periodic current of single electrons, arises through a tunnel junction circuit as a consequence of a DC bias. We study the zero-temperature noise spectrum of a tunnel junction in different resistive environments with the aim to determine the boundaries of the SETOs regime and quantify their quality in terms of periodicity. We then discuss the finite-temperature generalization and the possibility to account for the effects of quantum fluctuations
Herrmann, Lorentz. "Carbon Nanotubes as Cooper Pair Beam Splitters." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00528938.
Full textMouafo, Notemgnou Louis Donald. "Two dimensional materials, nanoparticles and their heterostructures for nanoelectronics and spintronics." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAE002/document.
Full textThis thesis investigates the charge and spin transport processes in 0D, 2D nanostructures and 2D-0D Van der Waals heterostructures (VdWh). The La0.67Sr0.33MnO3 perovskite nanocrystals reveal exceptional magnetoresistances (MR) at low temperature driven by their paramagnetic shell magnetization independently of their ferromagnetic core. A detailed study of MoSe2 field effect transistors enables to elucidate a complete map of the charge injection mechanisms at the metal/MoSe2 interface. An alternative approach is reported for fabricating 2D-0D VdWh suitable for single electron electronics involving the growth of self-assembled Al nanoclusters over the graphene and MoS2 surfaces. The transparency the 2D materials to the vertical electric field enables efficient modulation of the electric state of the supported Al clusters resulting to single electron logic functionalities. The devices consisting of graphene exhibit MR attributed to the magneto-Coulomb effect
Phoenix, Thomas. "Noise and the full counting statistics of a Coulomb blockaded quantum dot." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1543/.
Full textPierre, Mathieu. "Transport mono-électronique et détection de dopants uniques dans des transistors silicium." Phd thesis, Grenoble, 2010. http://www.theses.fr/2010GRENY045.
Full textWe present low temperature electronic transport measurements in silicon-on-insulator nano-MOSFETs. Their electrical properties depend in particular on the junctions between the reservoirs and the transistor channel, determined during fabrication by the spacers deposited on both sides of the gate. The behaviour differences are emphasized at low temperature. In ultra-scaled transistors, with a typical gate length of 30 nm, dopants diffusion during activation annealing can result in a single dopant well coupled to the reservoirs located in the middle of the channel, below the gate. It is revealed at low temperature below the transistor threshold by resonant tunnelling through its energy levels. An estimation of its ionization energy gives an enhanced value as compared to the bulk value, attributed to the dielectric confinement of the donor. On the contrary, electrons can be confined in the transistor channel by high enough access resistances. Thus samples turn at low temperature into single electron transistors, with the island located below the gate. It is extended to coupled dots systems, by depositing several gates between source and drain. Their behaviour depends on the distance between gates and on spacers length. These systems are used to transfer a single electron
Hourdakis, Emmanouel Spyros. "Electrical measurements at the micro scale air breakdown and si coulomb blockard devices /." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7619.
Full textThesis research directed by: Dept. of Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Pierre, Mathieu. "Transport mono-électronique et détection de dopants uniques dans des transistors silicium." Phd thesis, Université de Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00540644.
Full textLepage, Hadrien. "Modélisation de solides à nanocristaux de silicium." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00753248.
Full textRuess, Frank Joachim Physics Faculty of Science UNSW. "Atomically controlled device fabrication using STM." Awarded by:University of New South Wales. Physics, 2006. http://handle.unsw.edu.au/1959.4/24855.
Full textKubala, Björn [Verfasser]. "Quantentransport durch Coulomb-Blockade-Systeme / von Björn Kubala." 2006. http://d-nb.info/982839146/34.
Full text林玉敏. "Coulomb Blockade Oscillation in Closed Quantum Dot Systems." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/pbfns9.
Full textChung, Chung-Dau, and 仲崇道. "Environment impedance dependence of the Coulomb blockade behavior in point-contact single junctions." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/02413726181465854094.
Full text國立清華大學
物理學系
97
In this thesis work, the effects of environment on Coulomb blockade behavior in point-contact single junctions are studied experimentally. The devices consist of a lead top-electrode and a cobalt bottom-electrode which are separated by a thin Si3N4 membrane with a nanopore within which the two electrodes form a junction. The transport behaviors of the point-contacts with different contact areas were investigated for temperatures ranging between 2K and 300K. At room temperature, all devices exhibited linear current-voltage (IV) characteristics with a well defined asymptotic resistance Ra. The devices showing high resistance (Ra >RK≡h/e2) at room temperature exhibited insulating behavior with the zero-bias resistance Ro increases with decreasing temperature, and the IV curves showed a suppression in current at low-bias voltage region. On the contrary, the devices showing low resistance (Ra < RK) at room temperature exhibited metallic behavior with Ro decreases with decreasing temperature, and the IV curves were linear in the voltage region of interest. A model circuit was proposed to explain the observed behaviors. This model consists of a single tunnel junction (a capacitor shunted with a tunnel resistor) connecting in series with environment of variable impedance. The single junction represents the point contact, which sees an environment comprising randomly stacked metal grains. The IV and Ro(T) characteristics of this model circuit were calculated based on P(E) theory which describes the probability for energy exchange between tunneling electrons with energy E and the environment of various impedance, and a good agreement was obtained.During the course of device fabrication, we noticed the presence of chimney metal structures surrounding the nanopores. The chimneys are considered to be formed by nucleation process at the edge of the Si3N4 pores because this process can be observed by cooling the substrates with LN2. The nucleation process has been tested using different evaporation methods, evaporation rates with various metals and is found to be very robust.
Qi, Xiaoya. "Ground-state properties of one-dimensional systems and the physics of the Coulomb blockade /." 2003. http://wwwlib.umi.com/dissertations/fullcit/3091134.
Full textKreupl, Franz [Verfasser]. "Coulomb-Blockade bei Raumtemperatur in selbstorganisierten Arrays von Pt-Clustern / vorgelegt von Franz Kreupl." 2000. http://d-nb.info/97105004X/34.
Full textKang, Tzu, and 熊子綱. "Effects of Coulomb blockade and interdot hopping on the thermoelectric properties of serially coupled quantum dots." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/62409957977719632617.
Full text國立中央大學
電機工程研究所
100
In this thesis, we theoretically investigate the thermoelectric properties of a serially coupled quantum dot system (double quantum dots embedded in a nanowire connected to metallic electrodes ) by a two-level Anderson model. The charge and heat currents in the Coulomb blockade regime are calculated by the Keldysh-Green function technique. We study the following effects on the figure of merit (ZT) of system:1) electron interdot hopping strengths (t_AB) and Coulomb interactions, and 2) quantum dot energy levels above and below the Fermi energy (E_F) of electrodes. We also study the sign variation of Seebeck coefficient with respect to equilibrium temperature. When QD energy levels are aboveE_F , the maximum ZT is suppressed by the electron Coulomb interactions. When QD energy levels are below EF, the maximum ZT is attributed to the electron Coulomb interactions. The optimization of ZT prefers that the interdot electron hopping strengths are larger than electron tunneling rates arising from the coupling between the QDs and the electrodes in the presence of phonon thermal conductance. We demonstrate that ZT is not a monotonic increasing function of interdot electron hopping strength (t_AB). In addition, the Seebeck coefficient is not sensitive to the electron Coulomb interactions when QD energy levels are above E_F (far away from E_F). When QD energy levels are below E_F, we find the sign changed in the Seebeck coefficient with respect to temperature, which indicates that we can manipulate temperature to control the bipolar effect of junction system.
Spanheimer, Daniela Cornelia. "Dynamische Leistungsverstärkung bei GHz Frequenzen und Speichereigenschaften von nanoelektronischen GaAs/AlGaAs Transistoren." Doctoral thesis, 2009. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-37589.
Full textDynamical Charging and Discharging of laterally aligned quantum dot structures We can demonstrate that the direct positioning enables us to embed quantum dots with given periods to each other of only a few 100 nm and therefore with a defined density into the memory-structures. For low temperatures, well defined Coulombblockade can be observed. The analysis of the measured diamond patterns allows the determination of the dimension and the charging energy of the embedded quantum dots in the channel. The memory properties of these quantum dots were analyzed and discussed in terms of the hysteresis width DeltaVth which depends on the channel width, the applied drain voltage and the device temperature. The measurements reveal a dependence of the threshold voltage on the channel width of the structure. For devices with a wide channel the current transport sets in with negative applied gate voltages, in contrast to structures with narrow channels, requiring positive gate voltages to cause a current flow through the channel. To explain these results we assume that in large channels a higher negative voltage is necessary to deplete the charges out of the channel due to the higher charge density. To analyze the temperature stability of the charge states the threshold voltage as well as the hysteresis width is detected as a function of the temperature for different drain voltages in the range of 4.2K up to room temperature. It is determined that the hysteresis width decreases to a critical temperature before it rises again. For the investigation of the threshold voltage a difference between Vth,up and Vth,down is demonstrated. We assume that this difference is caused by the different charging behavior for increasing charge energies. In this work, lateral and vertical positioned InAs quantum dots could be demonstrated as a memory device operated at room temperature for the first time. Improved transistor functionality caused by gate leakage currents in nanoscaled Three Terminal Structures Further we investigate the role of gate leakage on the drain current in a monolithic, unipolar GaAs/AlGaAs heterostructure based on three leaky coupled contacts. Two in-plane barriers, defined by rows of etched holes in a two-dimensional electron gas, separate the leaky gate from the central drain and the drain from the source. Because of this the internal resistance of the structure can be appreciably decreased. It should be noted that the observed differential voltage amplification in the gate leakage regime of the studied structure is by far larger compared to the voltage amplification of any in-plane wire transistor fabricated from the same wafer, which were controlled by two non-leaking in-plane gates. The calculated transconductance increases quadratically and not in a non-linear manner, as expected. A pronounced reduction of the drain current sets in when the gate starts to leak, pointing at a large parallel gate capacitor. We associate the gate-leakage current induced gating with a virtual floating gate induced by the space charge injected from the gate. The space charge can hereby be described by a parallel gate capacitor that can control a low dimensional channel lying nearby. High frequency measurements on Three Terminal Structures High frequency measurements for determination of the power gain in Three Terminal Structures are carried out at room temperature. To improve the high frequency properties of the investigated structures a special design was chosen, where the gold contacts for contacting the sample approach very closely the active switching region. The measurements show that negative gate voltages are much more efficient to the power gain than positive ones. For these voltage combinations a power gain > 1 dB for frequencies in the GHz range is detected, whereas the power gain saturates for higher voltages. This is interpreted in terms of the maximum number of charges in the active region between the gold contacts. Furthermore an answer to the fundamental obstacle of the impedance mismatch for high frequency measurements on nanoelectronic structures with high internal resistance is given. Such a matching between the device and the measurement setup is necessary to reduce signal reflections and therefore increase the gain. To match the impedances, an impedancematching- network on a PCB-plate (printed circuit board) via integrated stubs was realized. Simulation data of the sample in connection with the matching-network is in very good agreement with the experimental data. Using the network reduces the simulated reflection coefficient and simultaneously raises the transmission coefficient. The measurements also show a significant improvement of the power gain behaviour