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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Characterization Of Ingaas Quantum Dot Chains, Tyler Drue Park
Characterization Of Ingaas Quantum Dot Chains, Tyler Drue Park
Theses and Dissertations
InGaAs quantum dot chains were grown with a low-temperature variation of the Stranski-Krastanov method, the conventional epitaxial method. This new method seeks to reduce indium segregation and intermixing in addition to giving greater control in the growth process. We used photoluminescence spectroscopy techniques to characterize the quality and electronic structure of these samples. We have recently used a transmission electron microscope to show how the quantum dots vary with annealing temperature. Some questions relating to the morphology of the samples cannot be answered by photoluminescence spectroscopy alone. Using transmission electron microscopy, we verified flattening of the quantum dots with annealing …
Current Development Of Quantum Dots Based Electrochemiluminescence Immunosensors, Ling-Ling Li, Qian Lu, Jun-Jie Zhu
Current Development Of Quantum Dots Based Electrochemiluminescence Immunosensors, Ling-Ling Li, Qian Lu, Jun-Jie Zhu
Journal of Electrochemistry
Electrochemiluminescence exhibits the merits of both luminescence and electrochemistry analysis, and has been extensively employed in biosensors. Quantum dots are considered one of the three main kinds of electrochemiluminescence luminophores due to their unique properties. This paper briefly reviews the classification and signal amplification technology of quantum dots based electrochemiluminescence immunosensors. Future research trends are also suggested.
Graphene-Based Semiconductor And Metallic Nanostructured Materials, Abdallah Zedan
Graphene-Based Semiconductor And Metallic Nanostructured Materials, Abdallah Zedan
Theses and Dissertations
Exciting periods of scientific research are often associated with discoveries of novel materials. Such period was brought about by the successful preparation of graphene which is a 2D allotrope of carbon with remarkable electronic, optical and mechanical properties. Functional graphene-based nanocomposites have great promise for applications in various fields such as energy conversion, opteoelectronics, solar cells, sensing, catalysis and biomedicine. Herein, microwave and laser-assisted synthetic approaches were developed for decorating graphene with various semiconductor, metallic or magnetic nanostructures of controlled size and shape. We developed a scalable microwave irradiation method for the synthesis of graphene decorated with CdSe nanocrystals of …
Energetics And Dynamics In Quantum Confined Semiconductor Nanostructures, Jessica Hoy
Energetics And Dynamics In Quantum Confined Semiconductor Nanostructures, Jessica Hoy
All Theses and Dissertations (ETDs)
The ability to tune the band-gap energies of semiconductor quantum dots, nanoplatelets, and quantum wires, their significant absorption cross sections, and high photoluminescence quantum yields make these nanostructures promising moieties for use in optoelectronic devices, solar concentrators, chemical sensors, and biological labels. The variable dynamics of the electron-hole pairs that occur within semiconductor nanostructures, however, can complicate the utility of these devices. The variability of the dynamics is born from the different paths accessible for the charge carriers to undergo. In this work, three pathways are proposed to be of primary consequence, namely, electronic intraband relaxation, coupling to surface-mediated processes, …
Hetero-Junctions Of Boron Nitride And Carbon Nanotubes: Synthesis And Characterization, Yoke Khin Yap
Hetero-Junctions Of Boron Nitride And Carbon Nanotubes: Synthesis And Characterization, Yoke Khin Yap
Department of Physics Publications
Hetero-junctions of boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) are expected to have appealing new properties that are not available from pure BNNTs and CNTs. Theoretical studies indicate that BNNT/CNT junctions could be multifunctional and applicable as memory, spintronic, electronic, and photonics devices with tunable band structures. This will lead to energy and material efficient multifunctional devices that will be beneficial to the society. However, experimental realization of BNNT/CNT junctions was hindered by the absent of a common growth technique for BNNTs and CNTs. In fact, the synthesis of BNNTs was very challenging and may involve high temperatures (up …
Effects Of Gaas(Sb) Cladding Layers On Inas/Alassb Quantum Dots, Paul J. Simmonds
Effects Of Gaas(Sb) Cladding Layers On Inas/Alassb Quantum Dots, Paul J. Simmonds
Paul J. Simmonds
The structural and optical properties of InAs self-assembled quantum dots buried in AlAs0.56Sb0.44 barriers can be controlled using GaAs1−xSbx cladding layers. These cladding layers allow us to manage the amount of Sb immediately underneath and above the InAs quantum dots. The optimal cladding scheme has a GaAs layer beneath the InAs, and a GaAs0.95Sb0.05 layer above. This scheme results in improved dot morphology and significantly increased photoluminescence (PL) intensity. Both power-dependent and time-resolved photoluminescence confirm that the quantum dots have type-II band alignment. Enhanced carrier lifetimes in this quantum dot system …
Quantum Computing With Steady State Spin Currents, Brian Matthew Sutton
Quantum Computing With Steady State Spin Currents, Brian Matthew Sutton
Open Access Theses
Many approaches to quantum computing use spatially confined qubits in the presence of dynamic fields to perform computation. These approaches are contrasted with proposals using mobile qubits in the presence of static fields. In this thesis, steady state quantum computing using mobile electrons is explored using numerical modeling. Firstly, a foundational introduction to the case of spatially confined qubits embodied via quantum dots is provided. A collection of universal gates implemented with dynamic fields is described using simulations. These gates are combined to implement a five-qubit Grover search to provide further insight on the time-dependent field approach. Secondly, the quantum …
Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, K. N. Chauhan, D. Mark Riffe, E. A. Everett, D. J. Kim, H. Yang, F. K. Shen
Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, K. N. Chauhan, D. Mark Riffe, E. A. Everett, D. J. Kim, H. Yang, F. K. Shen
All Physics Faculty Publications
Using 800 nm, 25-fs pulses from a mode locked Ti:Al2O3 laser, we have measured the ultrafast opticalreflectivity of MBE-grown, single-layer In0.4Ga0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and …