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 36 for “"photoresponse"”.
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Nanostructured BaTiO3 Thin Films for Enhanced Photoresponse
Light-driven devices are of great importance among emerging technologies such as artificial intelligence and quantum computing, owing to their remote-control ability, ultrafast response and low energy consumption. Ferroelectric materials have attracted considerable interest in this field. On the …
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Photoresponse and conductance mechanisms in nanoscale superconductor normal-metal point contacts
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.
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Modeling the effects of surface plasmon resonance on hot electron collection in a metallic-semiconductor photonic crystal device
… the range from 400 nm to 800 nm, the sub-bandgap photoresponse shows a single peak centered at 590 nm, which is identified as the surface plasmon resonant wavelength of this device. We develop a theoretical model of hot electron generation, transport and injection in this device incorporating the …
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Fabrication and Optoelectronic Characterization of Nanoscale Resonance Structures
… Yagi-Uda based device exhibited two maxima in photoresponse at 1110 nm and 1690 nm. Effective wavelength scaling was applied to the Yagi-Uda nanoantenas, and consistency was demonstrated between the theoretical effective wavelength and experimental photoresponse maxima. The spectral response of …
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Regulation of the catalytic and allosteric properties of photoreceptor phosphodiesterase (PDE6) by the glutamic acid-rich protein-2 (GARP2)
… the sensitivity, amplitude, and kinetics of the photoresponse during excitation, termination and adaptation to light stimulation in rod and cone photoreceptors. The central hypothesis of this thesis is that one PDE6 binding partner, the glutamic acid-rich protein (GARP2), may regulate PDE6 to …
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Fabrication of Zinc Nitride Thin Films using RF Magnetron Sputtering Deposition for Optoelectronic Applications
… spectrometry, and Hall effect measurement. The photoresponse of the zinc nitride photoconductors was also studied under the irradiation of white light and NIR light. The as-deposited zinc nitride thin films were relatively soft and densely packed with smooth surface. It possesses a narrow …
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Technologies for Room-Temperature Mid-Infrared Photodetection using Graphene
… is a particularly promising 2D material whose photoresponse has been shown to range from visible to terahertz wavelengths and enjoys fairly mature synthesis and processing technology. Thus, in this thesis, I demonstrate two different mid-infrared systems with novel features enabled by graphene …
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Semiconducting properties of the passive films on copper
… have been investigated through capacitance, photoresponse and kinetic measurements. Mott-Schottky plots show that the passive films on copper are p-type semiconductors. The metal deficits form the electron acceptors, which give rise to p-type conductivity. The passive films show photovoltages …
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HYDRODYNAMIC AND BALLISTIC TRANSPORT IN ULTRA-CLEAN 2D ELECTRON SYSTEMS
… on tunnelling in p-n junctions and on photoresponse of a point contact in graphene.
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Mid-Wave and Long-Wave Single Uni-polar Barrier Infrared Detectors Based on Antimonide Material Systems
… to help elucidate effects on dark current and photoresponse. Mid-wave superlattice nBn detectors with different absorber doping conditions have been studied as well. Dark current was found to be decreased by lightly doping the barrier layer n-type. variations of the nBn design, such as the pBn …
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Understanding and engineering electronic and optoelectronic properties of 2D materials and their interfaces
… Furthermore, the layer number dependent spectral photoresponse of MoS2 is investigated, which shows the highest response in single layer (1L) region. The photoresponse decreases for increasing layer number, but increases again between 4L and 1 OL due to increased light absorption. The …
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Terahertz photomixing spectroscopy of two-dimensional semiconductor plasmons
… of the mechanism underlying the detectors photoresponse, namely plasmons. Although two-dimensional plasmons were first observed in semiconductors in 1978, to date, their physical properties, for example scattering and absorption cross section, are relatively unknown. The primary purpose of …
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Study on the photoelectric hot electrons generation and transport with metallic-semiconductor photonic crystals
… (FWHM) of 235 nm centered at 590 nm is observed. Photoresponse enhancement factor of 12.28 at 639 nm compared to a flat chip is also measured. Applications of these results could lead to low-cost and robust photoelectrochemical device such as full-spectrum solar water splitting.
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Novel electronic behaviors in graphene nanostructures
… of graphene, such as high mobility, Berry phase, photoresponse mediated by hot carriers, and at the same time acquire new features due to nanoscale heterogenities. In this thesis, I explore the novel electronic behaviors which emerge in this fashion. I focus on two types of systems: (i) …
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MULTICOLOR INFRARED DETECTION USING STEP QUANTUM WELLS
… The sample was designed to have multicolor photoresponse by using bound-to-bound and bound-to-continuum intersubband transitions. The quantum well structure was composed of InxGa1-xAs, GaAs and AlyGa1-yAs layers. The sample was grown by molecular beam epitaxy (MBE) on (100) semi-insulating …
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Strechable crumpled graphene photodetector with plasmonically-enhanced photoresponsivity
… hybrid systems succeeded in the enhancement of photoresponse, but showed limited mechanical stretchability. Here, we demonstrate a crumpled graphene-gold nanoparticles (AuNPs) hybrid structure photodetector with ~1200% enhanced photoresponsivity compared to conventional graphene photodetector …
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Probing valley and magnetic photoexcitations in 2D crystals and their heterostructures
… its ligand-field and charge-transfer-dominated photoresponse, which broadens the landscape of 2D material photoexcitations beyond excitons. Finally, we combine ultrathin layers of CrI3 with monolayer WSe2, where we discover unprecedented control of valley excitons in monolayer WSe2 by magnetic …
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Au nanorods-semiconductor nanowire hybrid nanostructures : nanofabrication techniques and optoelectronic properties
… and injection mechanism underlying the photoresponse is investigated both experimentally and theoretically. The miniaturized, tunable and integrated capabilities offered by metal nanorodssemicondictor nanowire device architectures presented in this thesis work could have an important …
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First-principles investigations of transition metal hyperdoped silicon and germanium for intermediate band engineering
… incoming solar spectrum. Additionally, if the photoresponse of silicon could be extended to the infrared, silicon could be used to replace more expensive germanium based detectors. My thesis research focuses on defect engineering of silicon to extend the photoresponse to the infrared regime. …
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Ab initio study of nonlinear and vibrationally-controlled optoelectronic responses in semiconductors
… and use this method to better understand the photoresponse of monolayer MoS2. Then, we discuss two potential mechanisms that could contribute to the BPVE. While these mechanisms have been discussed in model systems, it is difficult to determine their relevance in real materials. We outline new …
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