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 110 for “"carrier concentration"”.
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Spin-Orbit Coupling in SrTiO3/Si Thin Films at High Carrier Concentration
… Our group has studied the sample having lower carrier concentration (≤ 10¹⁴, cmˉ²) which shows Weak- localization effect. As the carrier concentration increases ( (1 − 2) × 10¹⁴, cmˉ²), we see WAL effect which occur due to spin -orbit coupling. The thesis describes the results on my thesis …
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Carrier concentration and dye type effect on carrier and dye uptake of dacron type 54 yarn in disperse dyeing of polyester
The effect of carrier concentration and dye type on carrier and dye uptake of Dacron type 54 yarn was determined. Disperse Red 60 and Disperse Yellow 54 dyes were used. 0-phenyl phenol was used with six different concentrations of this carrier (0, 1, 2, 3, 4 and 5 gm/l). Spun Dacron type 54 …
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Improved catalysts with properties controlled by semiconductor band engineering
Difficulties in achieving control over carrier concentration have impeded progress toward tailoring the carrier concentration in semiconducting oxide supports for metal catalysts. Such tailoring could make possible the intentional exploitation of the Schwab effect, in which the carrier …
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Neutron irradiation effects in gallium arsenide
… studied, after epitaxial layers doped with Si at concentrations in the range 1.35 $\times$ 10$\sp{15}$ to 1.60 $\times$ 10$\sp{16}$ cm$\sp{-3}$ were irradiated with reactor neutron fluences up to 1.31 $\times$ 10$\sp{15}$ cm$\sp{-2}.$ When the changes in carrier concentration, Hall mobility and …
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The Seebeck effect in thin film CdS and ZnₓCd₁₋ₓS
… The temperature dependence of mobility and carrier concentration is studied in CdS films of varying thicknesses (3 µm to 14.0 µm) and in Zn<sub>x</sub>Cd<sub>1-x</sub>S films of varying zinc content (0 ≤ x ≤ .35) . Scattering is found to be grain boundary dependent in all films except the …
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Processing and characterization of contacts on MBE-grown gallium nitride
… with high level of purity are grown, the carrier concentration is therefore low, and the resulting high resistivity of the bulk imposes some difficulties for capacitance-related measurements. This thesis deals with the problem of processing and characterization of contacts on highly …
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Thermogravimetric, thermopower, and electrical conductivity studies of the Ba₂YCu₃O₇₋ₓ system
… ranges studied.</p> <p>The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen …
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Defect engineering of polycrystalline titanium dioxide synthesized by atomic layer deposition
… methods for characterization and manipulation of carrier concentration, near-surface and near-interface electric fields, and magnetic ordering are lacking. The present work employs ALD as a film synthesis technique to allow precise control over TiO2 microstructure, crystallinity, and composition. …
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Annealing for intrinsic point-defect control and enhanced solar cell performance : the case of H₂S and tin sulfide (SnS)
… a strong absorption coefficient, high majority carrier mobility, and a promising initial report of a 1.3 % solar cell. Tin sulfide does not have the toxicity or scarcity issues that will plague CdTe and CIGS thin film manufacturers as the PV industry grows toward the terawatt level. Growth of …
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Design of band-engineered photocatalysts using TiO2
Difficulties in achieving control over carrier concentration have impeded progress toward tailoring the electric fields in semiconducting oxide photocatalysts based on principles of electronic band-engineering drawn from classical microelectroncis. The present work demonstrates such principles …
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Investigation of defect formation and control in poly-crystalline anatase titanium dioxide
… processing. Among its drawbacks is a high native carrier concentration likely due to the formation of oxygen vacancies and their clustering at grain boundaries which impede hole mediated photocatalytic reactions. Previous efforts to defect engineer atomic layer (ALD) grown TiO2 were successful by …
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Electronic Transport in Thermoelectric Bismuth Telluride
… in the semiconductor industry for determining carrier types, carrier concentration and mobility. Further, these transport parameters are used to determine the thermal to electrical conversion efficiency of a thermoelectric material. The Boltzmann transport equation was used to analyze the …
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Semiconducting tin oxide thin films on glass
… are found to be n-type semiconductors. The large carrier concentration (~10¹⁹/cm³) of these films causes the donor level to blend into an impurity band. Annealing the stannic oxide film results in a diffusion of glass components on the film surface which is also accompanied by the increase in the …
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New strategies for application of defect engineering to TiO2 based photocatalytic materials
… to include portions of the visible spectrum, but carrier lifetime is reduced as the same dopants act as recombination centers. Dopant free defect engineering has demonstrated that the amorphous synthesis route has a direct result on the native carrier concentration of a polycrystalline finished …
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Non-metallic nanostructures for light-driven chemistry and catalysis
… to fulfill the requirement of large enough free carrier concentration. Within this context, semiconductor nanocrystals, namely two forms of copper-deficient cuprous sulfide (Cu₂₋ₓS), are studied in two separate investigations to gain new insights into their light harvesting abilities. In one …
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Disorder and Doping in the Oxygenated Electron-doped Superconductor PCCO
… is due to an interaction between the charge carriers and the magnetic moments. I found that low carrier concentration anatase phase films did not exhibit an anomalous Hall effect, whereas high carrier concentration rutile phase films do. The presence of the anomalous Hall effect at this point …
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Photoacoustic measurement of bandgaps of thermoelectric materials
… All three properties are affected by the carrier concentration of the thermoelectric material. In practice, tedious trial-and-error testing is needed to determine the optimal carrier concentration for the maximum figure-of-merit, ZT. Theory and computer simulations of thermoelectric …
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Experimental investigations on the influence of curvature and materials on near-field thermal radiation
… thermal radiation can be tuned by changing carrier concentration. Using a doped silicon sphere, we demonstrate the tuning effect of near-field thermal radiation between doped silicon surfaces. This demonstration shows the potential application of near-field thermal radiation on controlling …
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Surface Acoustic Waves Propagation and Coupling Fields in Piezomagnetic and Piezoelectric Semiconductor Layered Structures
… coupling effect of mechanical-electro-carrier, and its multiple properties are adapting to the needs of the rapid development of electronic devices. In recent years, the research on multi-field coupling behaviors and waves modulation of PSs has become one of the hot topics. By …
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Electrical studies of silicon and low K dielectric material
… (CV) measures the overall net carrier concentration and a built-in voltage for a diode junction. Deep level transient spectroscopy (DLTS) as one of the most sensitive electrical measurement techniques can detect electrically active impurity concentration on the level of 10-1 to …
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