Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 98 for “"quantum confinement"”.
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Increasing the bit density of a quantum confinement physically unclonable function
… institute. We study the recently proposed quantum confinement physically unclonable function by Roberts, et al. that utilises resonant tunnelling diodes (physical representation of a quantum well) and atomic scale imperfections for applications in cryptography and identification. Presently …
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An analytical framework for field electron emission, incorporating quantum- confinement effects
… shrink to nanoscale dimensions, the effects of quantum confinement of the electron supply and electric field enhancement at the emitter tip play a significant role in determining the emitted current density (ECD). Consequently, the Fowler-Nordheim (FN) equation, which primarily applies to field …
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The effect of quantum confinement on the thermoelectric figure of merit
… transport principle in the Si/Si1-xGex quantum well superlattice (two-dimensional) system and in the Bi quantum wire (one-dimensional) system. In bulk form, Si1_xGex is a promising thermoelectric material for high temperature applications. The Si/Si1 _xGex quantum well superlattice …
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Quantum confinement effects on light absorption in Germanium for solar energy conversion
… non-toxic, mono-elemental nanostructures (as Si quantum dots, C nanotubes, Ge nanowires, et al.) thanks to high purity and mature technology. Moreover, fascinating effects due to quantum confinement in this nanostructures can be effectively exploited for energy production in photovoltaics …
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The role of quantum confinement effects in the visible photoluminescence from silicon nanoparticles
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997.
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A Study of the Nucleation and Formation of Multi-functional Nanostructures using GaN-Based Materials for Device Applications
… to investigate the relationship between quantum confinement (and/or piezoelectric polarization) and the dot size. For dot height < 4.1nm, the confinement effect is larger than the piezoelectric effect, otherwise the piezoelectric effect is more dominant. In addition, GaN nanostructures …
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Transport properties along the channel of a Hemt
… it is inherently assumed that the variation of quantum confinement along the channel from the source to the drain is about the same and therefore, the transport properties are independent of position and only dependent on the electric field along the channel. In this study, the scattering rates …
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Germanium Nanostructures for Efficient Light Harvesting Devices
… of Ge NS depends not only by size through quantum confinement effects, but many other parameters can concur in controlling their optical behavior, especially for what concerns the optical bandgap. Discerning the role of these parameters and controlling their effects in the light absorption …
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Quantum-confined excitons in 2-dimensional materials
… potential of these materials as a platform for quantum devices: develop a method by which we can deterministically create single-photon emitting sites in 2d-TMDs, in large-scale arrays. These we call quantum dots (QDs): quantum confinement potentials within semiconductor materials which can trap …
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Effect of controlled oxidation processes on the emission and excitation of porous silicon
… Nevertheless, there is a growing consensus that quantum confinement in nanocrystallites is an important element of this mechanism. However, there are two competing models, both based on quantum confinement, namely bulk-like radiative recombination and novel radiative surface state recombination. …
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The optical properties of bismuth nanowires
… present even for nanowires too large to exhibit quantum confinement, thus showing that the absorption results from a surface-induced effect and not from quantum confinement. The enhanced optical absorption in nanowires over bulk bismuth is attributed to a surface term in the matrix element which …
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Design, fabrication, and characterization of low-dimensional quantum devices
… as modulation-doped field effect transistors and quantum well lasers. High resolution lithography and pattern transfer techniques now make it possible to further restrict the electronic motion to lower dimensions. A variety of interesting quantum confinement phenomena have been observed in these …
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Electronic and optical characterisations of silicon quantum dots and its applications in solar cells
… and electrical properties of crystalline silicon quantum dots (SiQDs) are examined for application to silicon based tandem cells. The approach has been to concentrate on all silicon devices by taking advantage of quantum confinement in low-dimensional Si. RF magnetron co-sputtering provided the …
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Theory and modeling of field electron emission from low-dimensional electron systems
… and material can be derived. The effects of quantum confinement and emitter tip geometry on the properties of emission were investigated by utilizing the framework to derive models for: i) a highly-curved, nanoscale, metal emitter tip; ii) a bulk silicon emitter with a surface quantum well …
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Development of Nanoprobes for the Biological Imaging Using Positive Charged Quantum Dots and Upconversion Nanoparticles
… unique physicochemical properties due to the quantum confinement effect. Semiconductor quantum dots (QDs) or upconversion nanoparticles (UCNPs) exhibit interesting properties such as high photoluminescence, photostability, dual magnetic/optical modality. In this study, biocompatible and stable …
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INVESTIGATION OF ELECTRIC AND THERMOELECTRIC PROPERTIES OF GRAPHENE NANORIBBON
… at 150K, which might due to the enhanced quantum confinement effect in GNR.
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Fabrication and characterization of compound semiconductor nanostructures
… to have their performance improved by the use of quantum confinement in the active region with sizes in the range of tenths of nanometers. The decrease in volume of the active region and the modification in the density of states in quantum structures is predicted to improve the threshold current, …
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Electronic, Optical, and Thermal Properties of Reduced-Dimensional Semiconductors
… and renewable energy. Because of the unusual quantum confinement and enhanced surface effect of reduced-dimensional materials, traditional empirical models suffer from necessary but unreliable parameters extracted from previously-studied bulk materials. In this sense, quantitative, …
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Ab initio Beschreibung der elektronischen Struktur und der Transporteigenschaften von metallischen Nanodrähten
… and shape of the cross-section is discussed. The quantum confinement of the eigenstates is analysed. By comparing the results of the Na and Cu wires, the influence of the d-electrons is shown. Based on the Landauer theory of transport the conductance is obtained within a Green's function …
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Effect of size and surface structure manipulation on the luminescent properties of silicon nanoclusters
… materials with crystalline order and molecules. Quantum confinement of the carrier wavefunction within such structures may significantly alter their electronic behavior. Additionally, the effect of surface reconstruction becomes substantial at this scale. This work investigated electronic and …
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