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 109 for “"carrier transport"”.
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Charge carrier transport in amorphous organic semiconductors
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
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Charge-carrier transport in amorphous organic semiconductors
… small bandwidth leads to localization of charge carriers and electron-hole pairs, called excitons. Thus, the charge-carrier mobility in organic semiconductors is generally much smaller than in their covalently-bonded, highly-ordered crystalline semiconductor counterparts. Indeed, one major …
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Carrier transport properties measurements in wide bandgap materials
This dissertation examines the carrier transport properties, diffusion length, effective carrier lifetime, and resistivity in two wide bandgap materials, GaN and diamond. A combination of two methods was used to obtain these transport properties. The two were optical beam induced current (OBIC) and …
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Theory of carrier transport in III-Nitride based heterostructures
… electronic structure, however models focusing on transport properties are less mature. This is in part due to the challenges of connecting a random alloy description of the underlying microstructure with transport models. This thesis addresses this difficult problem by developing and utilizing …
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Nanostructured photovoltaics : improving device efficiency and measuring carrier transport
… addition of the ZnO nanowire array and improved carrier collection due to the bulk heterojunction effect. Furthermore, electron beam-induced current (EBIC) was used to study charge transport in PbS QD films. It is shown that holes are the minority carrier in PbS QD films treated with …
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Field effect investigations of charge carrier transport in organic semiconductors
… technologies. The understanding of charge transport in these materials and minimizing electrical losses in organic devices is essential to improve device output. In this thesis the transport properties of charge carriers in solution processed organic semiconductors were investigated via …
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Graphene Based Chemical and IR Sensors and Correlated Carrier Transport
… In particular, graphene exhibits remarkably high carrier mobility up to 200,000 cm2 V-1s-1 in suspended form, as the charge carriers resemble Dirac fermions; and the carrier transport can remain ballistic up to 0.3 μm in ambient conditions. However, due to different sources of scattering, this …
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Optical properties and carrier transport in Si/ Si1-xGex nanostructures
… This study explores the optical properties and carrier transport in two different types of Si/Si _{1-x}Ge _xnanostructures: Ge nanowires (NWs) forming nanoscale heterojunctions with Si substrates and multilayers of SiGe clusters embedded into a Si matrix. Micron-long Ge nanowires grown on n^+ …
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Modeling of Charge Carrier Transport in Photoetching of Gallium Arsenide
… in a selectively illuminated semiconductor. The transport mechanisms associated with the etching process were studied. The model used the Galerkin Finite Element Method to solve the Poisson equation for the potential and the species balance equations for holes and electrons in two dimensions. …
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Carrier Transport and Electrical Conduction in Alloy-Mediated Graphene on Silicon
… achieved in the synthesis and establishment of transport properties of epitaxial graphene (EG) on 4H- and 6H-SiC, while equivalent progress using silicon (Si) as a platform (via a thin film of 3C-SiC) with reliable electrical transport measurements has not been elucidated to date, due to …
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Carrier transport in undoped and doped films of amorphous arsenic triselenide
The work reported in this thesis was carried out at the Physics Department of Dundee College of Technology between October 1978 and October 1981. The aim of the work was to examine the nature of the changes in electrical properties of amorphous chalcogenide films fabricated using different …
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The effects of strain on carrier transport in thin and ultra-thin SOI MOSFETs
… of scaling silicon film thickness. Electrical transport appears to be one of the limiting factors for scaling body thickness. As the silicon film thickness is reduced into the ultra-thin regime, where the film is thinner than the bulk inversion layer thickness, quantum confinement effects begin …
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Comprehensive inverse modeling for the study of carrier transport models in sub-50nm MOSFETs
Direct quantitative 2-D characterization of sub-50 nm MOSFETs continues to be elusive. This research develops a comprehensive indirect inverse modeling technique for extracting 2-D device topology using combined log(I)-V and C-V data. An optimization loop minimizes the error between a broad range …
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Charge carrier transport and recombination in semiconductors: Insights from statistical analysis and machine learning techniques
… thesis pioneers techniques to understand charge carrier dynamics in semiconductor materials, with the goal of advancing next–generation optoelectronic devices, with three main thrusts explored. In Chapter 4, efficient exciton energy transport in thin Ruddlesden-Popper perovskite flakes is …
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Purity matters : enhancing carrier transport properties in tin sulfide for photovoltaic applications by reducing impurity content
… photovoltaic applications, is hampered by poor carrier-transport properties, particularly minority-carrier lifetime. This study investigates the role of intrinsic and extrinsic crystallographic point defects on the electronic transport properties of SnS. High-purity SnS is grown via …
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Quantitative Carrier Transport in Quantum Dot Photovoltaic Solar Cells from Novel Photocarrier Radiometry and Lock-in Carrierography
… significantly, due to the not-well-understood carrier transport mechanisms and the lack of effective characterization techniques. Addressing these issues, carrier transport kinetics in CQD systems were studied to develop high-frequency dynamic testing and/or large-area quantitative imaging …
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Carrier transport, recombination, and the effects of grain boundaries in polycrystalline cadmium telluride thin films for photovoltaics
… in covalently-bonded semiconductors (a) act as carrier recombination centers, and (b) lead to localized energy states, causing carrier trapping. Despite significant research to date, the mechanism responsible for the superior current collection properties of polycrystalline CdTe solar cells has …
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The self-consistent simulation of carrier transport and its effect on the modulation response in semiconductor quantum well lasers
… and radiative recombination processes and the carrier transport mechanisms included in the simulator are first presented. Carrier transport in bulk regions of the device is modeled with drift-diffusion theory, and carrier fluxes at abrupt heterojunctions are treated with ballistic transport …
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Zero-field time-of-flight characterization of minority carrier transport in heavily carbon-doped gallium arsenide and indium gallium arsenide
… and in AlGaAs/GaAs HBT reliability. Minority carrier electron diffusion coefficients and lifetimes have been measured in heavily doped p-type GaAs and In$\sb{0.53}$G$\sb{0.47}$As using the zero-field time-of-flight (ZFTOF) technique in structures that simulate the base transport in HBTs. To …
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