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 27 for “"Auger recombination"”.
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Quantum saturation and condensation of excitons in copper (I) oxide
… to acoustic and low-lying optical phonons, Auger recombination, and ortho-para interconversion derived from experiment. The single adjustable parameter in our model is the optical-phonon cooling rate for Auger and laser-produced hot excitons. We show that the orthoexcitons move along the …
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Mid-IR type-II InAs/GaSb nanoscale superlattice sensors
… for high temperature operation, including fast Auger recombination rates and high thermal generation rate. These detectors operate at low temperatures (77K-200K) in order to obtain high signal to noise ratio. The requirement of cooling limits the lifetime, increases the weight and the total …
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Modeling and optimization of the transistor laser operation
… structure of the base. Second, the radiative recombination is analyzed from the first principles. The results indicate that the radiative recombination saturates in degenerately doped cases, where Auger recombination becomes dominant and deteriorates the quantum efficiency. Finally, this …
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Investigation of carrier dynamics in InN, InGaN, and GaAsBi by optical pump-probe techniques /
… and temperatures revealed that trap-assisted Auger recombination is the dominant recombination mechanism in MBE-grown InN layers at room temperature. Investigation of carrier dynamics in In-rich InGaN alloys revealed that density of fast nonradiative recombination centers increases with Ga …
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Growth and characterization of site-controlled InAs(Sb) nanowires for use in infrared photodetectors
… to low temperatures due to strong non-radiative Auger and surface recombination. Simple structures suffer from deleterious effects due to the high surface to volume ratio in nanowires which has limited emission to fixed wavelengths and low temperatures, until now. In this thesis the growth of …
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Towards broadly-tunable CMOS-compatible silicon light sources in the near-infrared
… lifetime of non-radiative processes such as Auger recombination. Nonetheless, the realization of an energy efficient silicon-based photon source could find broad applicability in areas such as ultra-large scale integration (ULSI), optoelectronic displays and lighting. Every practical solution …
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Many-body processes in the photophysics of colloidal semiconductor nanocrystals
… part of the thesis describes two studies of the "Auger" nonradiative recombination process whereby an electron-hole pair recombines while transferring its energy to a third particle. This mechanism is responsible for the short multiexciton lifetimes in NCs. In one study, we demonstrate a direct …
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Ultrafast Dynamics of Individual Air-Suspended Single-Walled Carbon Nanotube
… cross section, radiative lifetime, and Auger recombination lifetime). With the advancement in SWCNT sample preparation, studies of SWCNT intrinsic properties have shifted from ensemble to a single tube level, in which the ambiguities in elucidating intrinsic properties posed by the …
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Spectroscopy and rational chemical design of single emitters for quantum photonics
… and remarkable tunability of the biexciton Auger recombination rate. Mechanisms for the single emitter linewidths broadening and variable biexciton quantum yield are put forth. In the second part, I assess the optical coherence properties of PQDs as efficient single photon emitters at low …
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Defect investigations in InAs/GaSb type-II strained layer superlattice
… currents, and can use strain to suppress Auger recombination. In spite of these advantages, this material still faces several challenges, including low minority carrier lifetime, resulting from trap levels that cause Schockley-Read-Hall recombination. These low lifetimes lead to reduced …
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Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes
… to the roll-off. Finally, we study the effect of Auger recombination on QD-LEDs by varying the QD layer thickness. QD-LEDs with thicker QD layers exhibit lower peak EQEs and QD transient PL with stronger bi-exponential behavior. We attribute the strength of the bi-exponential behavior to the …
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InAs/Ga(In)Sb superlattice based infrared detectors using nBn design
… wavelength range. However, large tunneling and Auger dark currents due to low electron effective mass in MCT detectors require operation at cryogenic temperatures (77-100 K). The cooling requirement limits the lifetime, adds weight and expense and increases the power consumption of the infrared …
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Auger-mediated processes and photoluminescence in group iv semiconductor nanostructures
… of a fast non-radiative process attributed to Auger recombination. Moreover, this onset occurs earlier in structures with reduced physical dimensions, than in bulk material. The study of Auger-mediated processes in group IV nanostructures is therefore critical to understanding the physics of …
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Study of Type-I and Type-Ii Strained Quantum -Well Lasers
… But this advantage, is offset by severe Auger recombination rate. A new technique based on injection locking for measuring the linewidth enhancement factor is developed, and we extract the linewidth enhancement factor for the above three lasers. They are also calculated using the same …
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Thermal and Optical Simulations of Vertical Cavity Surface Emitting Lasers
… the thermal rollover have been examined. The Auger recombination process is found to be a main contributor to the thermal rollover in 980 nm oxide-confined VCSELs. We have also achieved a very good match between our simulated results and experimental data.
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Ultrafast Investigations of Exciton Dynamics in 0D and 2D Hybrid Semiconductor Nanomaterials
… shows a sublinear fluence dependence, excluding Auger recombination as the initiator of this process, in contrast with traditional nanocrystal systems. These results help illuminate the underlying mechanism of charging in perovskite nanocrystals, guiding future synthetic advances to improve …
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Single and multi-exciton dynamics in nanoscale semiconductors
… supports the proposed mechanism of biexciton-Auger recombination for the efficient suppression of the Bose-Einstein condensation of excitons. Third, we use two-dimensional rephasing spectroscopy to observe substantial inhomogeneous broadening due to large static disorder in monolayer …
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Strong-field Phenomena in Low-dimensional Materials at Terahertz Frequencies
… in QDs on gold by suppressing the trion-mediated Auger recombination. By effectively engineering the charge transfer between luminophore systems, we have developed a record-sensitive THz detector and polarimeter via THz-to-visible upconversion. We have investigated crossover between the …
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Investigation of InAs/GaSb superlattice based nBn detectors and focal plane arrays
… distributions of electrons and holes hinder the Auger recombination, leading to longer electron lifetime. However, the spatially indirect optical transitions lead to low absorption. The electron effective mass of the InAs/GaSb SLS (m*/mo \u2248 0.02-0.03) is larger than MCT (m*/mo \u2248 0.009) …
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Theoretical investigation of metal-cavity nanolasers and nanoLEDs and comparison with experiments
… Our study shows that the nonradiative recombinations, including the surface recombination and Auger recombination, dominate the threshold current. The high-speed modulation response of metal-cavity light-emitting devices is then investigated. Since the spontaneous emission plays an …
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