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 21 for “"PbSe"”.
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Theoretical characterisation of spheroidal PbSe/PbS Core/Shell colloidal quantum dot heterostructures
… devices. IV-VI semiconductor nanocrystals (PbS, PbSe) are of particular interest as candidates for the exploitation of MEG due to the narrow band gap, high confinement energies, and long radiative carrier lifetimes observed in these systems. In order to realise the full potential of MEG devices, …
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Magnetooptische Untersuchungen an Halbleitersystemen mit reduzierter Dimensionalität
… werden an dem ternären IV-VI Materialsystem PbSeTe durchgeführt. Bei der Entstehung von PbSe Quantenpunkten in PbEuTe Matrix ist es nicht auszuschließen, dass es an der Grenzfläche der Quantenpunkte und des Matrixmaterials zu Durchmischungen dieser beiden Materialien kommt und sich dadurch …
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Vapor-liquid-solid (VLS) growth of lead chalcogenide thin films for infrared sensing applications
… with improved performance. Lead selenide (PbSe) detectors are direct narrow band gap materials that have shown promise for relatively inexpensive IR sensing with modest cooling requirements. Adapting the vapour-liquid-solid (VLS) growth mechanism traditionally used for growing nanowires to …
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Electron transport in lead selenide nanocrystal arrays
… properties of arrays of lead selenide (PbSe) nanocrystals (NC's) of approximately 6nm diameter. The films become substantially more conducting when annealed at 400K, although no chemical changes of the capping layer occur at this low temperature. There is no evidence based on TEM images …
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Synthesis and characterization of semiconductor and semiconductor-metal nanoparticles
… Pb0-Partikeln synthetisiert werden. Sphärische PbSe-Nanopartikel werden für die Anwendung in hybriden Solarzellen untersucht. Der zweite Teil handelt von der neuen Synthese für die Herstellung von kolloidalen In2O3-Nanokristallen. Die Form der Nanokristalle konnte durch die Zugabe von Cu-Ionen …
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Cd3P2 Quantum Dots As Sources for Quantum Emission and Detection of Near-IR Radiation
… environments. Lead chalcogenides (e.g., PbS, PbSe), mercury chalcogenides (e.g., HgSe, HgTe), and InAs are the primary near-IR capable CQDs researched, but these species suffer from setbacks such as long carrier lifetimes (>1 µs, PbS/PbSe), toxic precursors and products (HgSe/HgTe), and …
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Experimental studies of the thermoelectric properties of microstructured and nanostructured lead salts
… the phonon mean free path. Samples of PbTe and PbSe were prepared by hot pressing nano-size and micro-sized particles and the thermal diffusivity, the Seebeck coefficient, and the electric conductivity of the samples were measured. The samples made from the nano-sized particles showed no …
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Ultra low thermal conductivity in layered disordered crystalline materials
… of sound of misfit-layer dichalcogenide films [(PbSe)m (TSe2)n]i (T = W or Mo, m = 1-5, n = 1-5) synthesized by the MER. The thermal conductivities of these nanoscale layered materials are 5-6 times lower than the predicted minimum thermal conductivity Λmin of PbSe. Thermal conductivity decreases …
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Highly tunable room temperature quantum cascade lasers
… This system was used to investigate the QCL, a PbSe photodiode was used as the detector. The investigation showed that the QCLs can be pulsed with electrical pulses from 50ns-200ns safely, that repetition rates up to 680kHz are feasible and that even at these extremely high repetition rates …
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Colloidal semiconductor quantum dots : from synthesis to photonic applications
… nanocrystals, more specifically PbS and PbSe quantum dots (Qdots) with a typical diameter of 2-10nm, using wet chemical techniques. These materials are promising for telecom applications, as their band gap depends on the particle size and is tunable over the entire near-infrared spectral …
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Many-body processes in the photophysics of colloidal semiconductor nanocrystals
… of up to 5.9 eV, and the CM yields observed for PbSe NCs at 3.1 eV were found consistent with bulk values. Reasons for the strong disagreement with prior measurements are discussed, and the low yields are theoretically accounted for. The second part of the thesis describes two studies of the …
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Singlet exciton fission, a multi-exciton generation process, in organic semiconductor solar cells
… C60 , perylene diimides, PbS quantum dots and PbSe quantum dots as acceptors.
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Development of low-temperature solution-processed colloidal quantum dot-based solar cells
… (260°C) sintered or sputtered ZnO/PbS (PbSe) QD devices. The initial device yield issue associated with the pinhole formation was addressed, and a procedure for the fabrication of reproducible devices was formulated. The demonstration of this device is a step towards low-cost solar cell …
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Protein-mediated nanocrystal assembly for floating gate flash memory fabrication
… this method, we demonstrated that colloidal PbSe and Co NCs in suspension can self-assemble into ordered arrays with a high density of up to 10¹²cm⁻². MOSCAP and MOSFET memory devices were successfully fabricated with the chaperonin protein mediated NCs, showing promising memory functions …
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Applications of spectral management in optoelectronic devices
… Here we present solar cells fabricated from PbSe nanorods which show external quantum efficiencies exceeding 100 %. This demonstrates the potential for substantial improvements in PV device performance due to MEG. Through spatial and spectral concentration, LSCs have the potential to reduce …
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The fabrication of TiO2 nanostructures on porous silicon for thermoelectric application
… TE materials are Bi2Te3-based alloys, PbTe, PbSe, SiGe, Mg2X (X = Si, Ge, Sn), skutterudite, and half-Heusler alloys. However, there are some problems arise since most of these rare earth alloy-based TE materials, such as Bi2Te3 and PbTe, suffer from thermal and chemical instabilities. …
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Bio-Nano Interfaces: Enzyme Immobilization for Biomimetic Energy Harvesting
… with 1-pyrenebutanoic acid, succinimidyl ester (PBSE) were used to immobilize porcine heart malate dehydrogenase (MDH) and citrate synthase (CS) on multi-walled carbon nanotubes (MWNTs). The effects of each method on the oxidation of L-malate (M) by MDH in the presence of CS are reported. …
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Metal Chalcogenide Nanocrystal Assembly: From Synthesis To Applications
… employed for other gel systems, including PbSe and CuSe.</p> <p>The photoluminescence (PL) response of highly porous CdSe aerogels to triethylamine (TEA) is investigated and compared to prior studies on single crystals and nanoparticle-polymer composites. As-prepared CdSe aerogels show …
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The mineralogical deportment of radionuclides in South Australian Ca-Au-(U) ores
… since the Pb-chalcogenides galena, clausthalite (PbSe) and altaite (PbTe) are often hosted within Cu-(Fe)-sulphides. Lead isotope values measured in-situ by laser ablation inductively coupled plasma mass spectrometry suggest an overwhelmingly radiogenic origin for Pb and thus extensive decoupling …
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Heat transport by phonons in crystalline materials and nanostructures
… lattice thermal conductivity of (PbTe)1-x/(PbSe)x nanodot superlattices (NDSLs) approaches the thermal conductivity of bulk homogenous PbTe1-xSe x alloys with the same average composition. On the other hand, I find that 3% of ErAs nanoparticles embedded in InGaAs is sufficient to scatter …
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