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.
Results
Showing 1 to 20 of 91 for “"carrier density"”.
-
The Hall Effect for Probing Conjugated Polymer Charge Transport in High Carrier Density Regimes
… is built around a central concept of different carriers in a polymer system having different degrees of average coupling, g, to a magnetic field. This is assumed to be described by a statistical distribution characterised by its average value, ⟨g⟩. This, and other parameters that can be …
-
Mobility and Saturation Velocity in Graphene on Silicon Dioxide
… analyzed with practical models including gated carriers, thermal generation, “puddle” charge, and Joule heating. Graphene mobility is characterized as a function of carrier density at temperatures from 300 to 500 K. In addition, electron drift velocity is obtained at high electric fields up to 2 …
-
Effects of energetic irradiation on materials and devices based on graphene and topological insulators
… study to fully explore the relationships between carrier density, disorder and Raman spectrum signatures. We find significant a dependence in the Raman spectra on both disorder and carrier density and extract an electron-phonon coupling strength as a function of disorder, which could prove …
-
Theory of graphene transport properties
… nature of transport in the highly inhomogeneous density and potential landscape, where activated transport across the potential fluctuations in the puddle regimes coexists with regular metallic diffusive transport. Our theoretical calculation explains the non-monotonic feature of the temperature …
-
Theoretical study of performance characteristics of semiconductor quantum dot lasers
… are included in the dissertation: 1) Effect of carrier-density-dependent internal loss in the optical confinement layer (OCL) on the characteristic temperature. Internal optical loss in a QD laser couples the confined-carrier level occupancy in QDs to the free-carrier density in the OCL. Due to …
-
Modeling of the output and transfer characteristics of graphene field-effect transistors
… vol. 3, p. 684, 2008] without assuming carrier density-dependent velocity saturation.
-
Thermoelectric and charge transport properties in doped and aligned conjugated polymers
… also facilitated the concurrent measurement of carrier density, enabling the plotting of its correlation with conductivity, Seebeck coefficient, mobility, and thermopower. Upon acknowledging PBTTT as a superior thermoelectric conjugated polymer, a critical progress was achieved through the …
-
Theory of Operating Characteristics of Quantum Dot Lasers with Asymmetric Barrier Layers
… QDs, in addition to the lasing ground state, carriers can be captured into excited states, where they then decay into the ground state. This excited-state-mediated capture impacts the operating characteristics, limiting the maximum output power and modulation bandwidth. Three separate cases …
-
Electronic properties of topological semimetal candidates ACd$_2$Pn$_2$ (A = Eu, Sr; Pn = As, Sb)
… highly insulating EuCd$_2$As$_2$ crystals with carrier density reaching as low as $2\times 10^{15}$ $\text{cm}^{-3}$. The magnetotransport measurements revealed a progressive decrease of the anomalous Hall conductivity by several orders of magnitude as the carrier density decreases. The behavior …
-
Transport properties of electrons in potassium bromide
… in crystals having high impedance ,and low carrier density was developed. The polaron mass in KBr was measured for the first time using this technique. In addition the static dielectric constant for KBr was determined from 4.2 K to room temperature.
-
Size Effects on Transport in Graphene
… important finding reveals that the charge carrier density in graphene nanoribbons was also width dependent, and that at a certain width the doping switched polarity from p-type to n-type. Graphene lateral spin-valves were fabricated with e-beam evaporated TiO2 as the pinhole-free and less …
-
Structural, magnetic and electric transport properties of metal substituted La₀.₇Sr₀.₃MnO₃
… formation of AF clusters, the change of electron carrier density and band structure, and complex interactions between electrons, phonons, and polarons"--Abstract, page iv.
-
Hall Effect Modeling in FEM Simulators and Comparison to Experimental Results in Silicon and Printed Sensors
… fields. Given a device geometry and charge carrier density and mobility, the models accurately calculated sensor resistance, Hall voltage under a normally-incident constant magnetic field, and expected offset from a population of Hall devices. The model was successfully matched against data …
-
The theory of Coulomb Drag in Graphene Systems
… of the position and width of the plasmon peak on carrier density and interlayer separation is enhanced.
-
Structure-property engineering and device fabrication of conjugated polymers by chemical vapor deposition
… of PEDOT is the difficulty of maintaining a high carrier mobility simultaneously with a high carrier density in this polymer.
-
Dynamically programmable surfaces for high-speed optical modulation and detection
… is also investigated in detail. A graphene carrier density spatiotemporal modulation technique is proposed and experimentally validated. This technique enables the demonstration of a compact graphene thermopile in the mid-infrared wavelengths and paves the way for future implementations of …
-
Exotic superconductivity in quantum materials
… and superconductivity in systems with low carrier density. We study new exciting properties of these materials and discuss possible microscopic mechanisms for exotic superconductivity. In Part I of this thesis, we explore the properties of two-component superconductors with strong …
-
Towards infrared plasmonics in graphene
… rely on controllable doping of graphene to high carrier densities in nanometer-scale structures. In this thesis, an experimental approach to generating nanoscale spatial carrier density modulation of graphene using electrolyte gates and crosslinked-PMMA screen is proposed and investigated. The …
-
Growth, Structural and Electrical Characterization of Topological Dirac Materials
… Hall resistance RA xy, Curie temperature Tc, carrier density and mobility were achieved. A substitutional Cr doping ranging from 7.5% to 38% was attained revealing a Tc reaching up to 186 K. Gated electrical measurements displayed a change in RA xy and carrier density by ~ 50% on applicating …
-
First Principles Studies of Magnetic Oxides, Spin-Driven Ferroelectricity, and the Effect of Polarization in the Chemistry of Functional Heterointerfaces
… of their technological applications. Employing density functional theory (DFT) with rotationally invariant Hubbard corrections, we present an extensive study of binary manganese oxides modeling their noncollinear spin patterns and computing their electronic structures in agreement with …
Page 1 of 5