Colloidal quantum dots are semiconducting nanocrystals covered in ligands as shown in figure 1. Synthesis and characterization of cds and cdse quantum dots by uvvis spectroscopy ekpekpo arthur and akpojivi lucky department of physics, delta state university abraka, nigeria. Quantum dots and silica dots a thesis presented to the faculty of the graduate school of cornell university in partial fulfillment of the requirements for the degree of master of science by diana lynne bull august 2004. Graphene quantum dots gqds have emerged as a new class of superior fluorescent materials owing to their unique properties of small size, biocompatibility, photostability, water solubility and large surface area. A study on the synthesis and the optical properties of inp. Part one is a selfcontained monograph which describes in detail the theoretical and experimental background for exploration of electronic states of the quantumconfined systems. Synthesis of lead sulfide quantum dots and their ligands for. Photoinduced synthesis of molybdenum oxide quantum dots for. I certify that i have read this dissertation and that, in my opinion, it. Theory, application, synthesis 2 therefore investigate the behavior of semiconductor crystals below this size. Quantum dots introduction to quantum dots quantum dots sound very exotic and indeed they are, in terms of the way they work, which is dictated by the rules of quantum mechanics.
Lower toxicity and broad band absorbance width makes cis qds appealing for light emitting diodes leds, lasers, sensors, bioimaging, solar cells, and computing. Graphene quantum dots for biological applications drntu. Con nement, synthesis, arti cial atoms and applications john sinclair univeristy of tennessee solid state ii instructer. The properties of quantum dots have caused researchers and companies to consider using them in several fields. This thesis mainly focuses on epitaxial qdembedded pn junction solar cells. Quantum dots description the emission and absorption spectra corresponding to the energy band gap of the quantum dot is governed by quantum confinement principles in an infinite square well potential. A quantum dot qd is a nanocrystal which ranges between 2 nm to 10 nm in size hornyak et al. Quantum dots 2 quantum dot qd is a conducting island of a size comparable to the fermi wavelength in all spatial directions. These unique qualities have made quantum dots an attractive material for a variety of scienti. Apr 18, 2016 quantum dots qds, nanocarriers for drugs, can help realize the targeting of drugs, and improve the bioavailability of drugs in biological fields. Synthesis and characterization of cds and cdse quantum. Highly tunable hole quantum dots in sige shellcore nanowires. Formation, structure, and properties of inasgaas quantum dots by simon huang a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy materials science and engineering in the university of michigan 2015 doctoral committee.
Various insitu and exsitu techniques along with importance of different capping layers for improving electronic properties of selfassembled quantum dots are also referred in this chapter. Second, quantum dots produce light themselves so they need no backlight, making them much more energy efficient an important consideration in portable devices such as cellphones where battery life is very. Synthesis, characterization, and applications 59 systems. Characterization of structure and composition of quantum.
First section includes the fundamental theories on excitons, trions, phase decoherence, and charge states. Thermal synthesis and characterization of size tuning glutathione capped cadmium selenide quantum dots a thesis presented to the faculty of the department of chemistry. The technical name for this ability to change the wavelengths of light absorbed by the quantum dots is bandgap engineering. Formation, structure, and properties of inasgaas quantum. Synthesis of lead sulfide quantum dots and their ligands. The advantages and disadvantages of selfassembled quantum dots are described in detail. The following survey of quantum dot applications introduces many of these uses. Characterization of structure and composition of quantum dots by transmission electron microscopy k. There are many possible applications of quantum dots in many different areas of industryscience. This thesis is a summary of the following papers published in international referee journals. In order for light to be absorbed by a solar cell the energy of the incoming light must be greater. In this paper, a lab experiment to demonstrate quantum phenomena was developed using carbon quantum dots cqds, a new carbonbased fluorescent nanomaterial, discovered in 2004.
Photoactivatable quantum dots in superresolution microscopy of muscle amal akel thesis prepared for the degree of master of science university of north texas december 2010 approved. Size, shape, composition, and electronic properties of inas. Synthesis and characterization of cds and cdse quantum dots. In this thesis, the quantum kinetics of semiconductor quantum dots coupled to the radiation. This thesis is concerned with the synthesis and characterisation of cis and ciszns coreshell. Thus it can be said that quantum dots will show a quantum. Quantum dots can be tuned to give off light of any color, so the colors of a quantum dot display are likely to be much more realistic.
Part one is a selfcontained monograph which describes in detail the theoretical and experimental background for exploration of electronic states of the quantum confined systems. Often called the artificial atoms, however the size is much bigger 100 nm for qds versus 0. The need for less toxic quantum dots qds has led to a significant number of investigations related to copper indium sulfide cis qds. Quantum dots can be synthesized to be essentially any size, and therefore, produce essentially any wavelength of light. Synthesis and characterization of pbte quantum dots. Theoretical studies on the effect of confinement on quantum. Carbon quantum dots cqds, c dots or cds, which are generally small carbon nanoparticles less than 10 nm in size with various unique properties, have found wide use in more and more fields. Dagotto april 9, 2009 abstract this paper will introduce ideas of quantum dots.
Synthesis and characterisation of cuins quantum dots. New ways of growing iiiv semiconductor quantum dots by integrating a ternary element or by. Thesis submitted in fulfilment of the requirements for the award of the degree of. The energy band gap increases with a decrease in size of the quantum dot. Lovingood, derek dean, synthesis and analysis of the quantum dot core and surface structures probed by solid state nuclear magnetic resonance 2010. By means of a simple and photoinduced method, four colors of molybdenum oxide quantum dots moox qds have been synthesized, using moco6 as the structural guiding agent and molybdenum source. For instance, larger quantum dots have a greater spectrum shift towards red compared to smaller dots, and exhibit less pronounced quantum properties. Quantum thesis pdf semiconductor i, christopher ronald hall, declare that this thesis entitled. Effect of builtin electric field on photovoltaic effect of inas quantum dots.
Larger quantum dots have a smaller bandgap and emit. In this thesis, we fabricate silicongermanium coreshell nanowire on bottom. Quantum dots are often referred to as artificial atoms with discrete atomiclike energy states resulting from quantum mechanical carrier confinement. Synthesis and analysis of the quantum dot core and surface. The research and applications of quantum dots as nano. The electron spin qubit can be coupled to excited states using an. Quantum dots and their applications understandingnano. This thesis presents an efficient method for cancer cell capture via cell linespecific antibody deposition and adsorption on nanoporous silica substrates using a method called microcontact printing and immunofluorescence detection through quantum dot. A quantum dot is a term usually applied to semiconductor nanocrystals with. Effectively, a quantum dot is something capable of confining a single electron, or a few, and in which the electrons occupy discrete energy states just as they would in an. Ian ferguson for being my thesis committee members, for their time. Functionalized quantum dots for dispersion in polymers and. Carbon quantum dots cqds, cdots or cds, which are generally small carbon nanoparticles less than 10 nm in size with various unique properties, have found wide use in more and more fields.
Study of quantum dots on solar energy applications. Qds are one of the first nanotechnologies to be integrated with the biological sciences and are widely anticipated to eventually find application in a number of commercial consumer and clinical products. In atoms the attractive forces are exerted by the nuclei, while in qds by background charges. The essential elements for the synthesis of quantum dots involve combining an appropriate metallic, or organometallic precursors such as zinc, cadmium or mercury species with a corresponding chalcogen precursor such as sulfur, selenium or tellurium species in coordinating organic solvent at. Johnson charge sensing and spin dynamics in gaas quantum dots abstract this thesis describes a series of experiments which explore and the technique of charge sensing in gaasalgaas quantum dot devices, then use charge sensing as a tool to investigate spin and charge dynamics. Conversely, the smaller particles allow one to take advantage of more. Synthesis and characterisation of cuins 2 quantum dots matthew booth. In general, the hamiltonian of an electronhole pair in a large semiconductor is given as h h 2 2m h r2 h h2 2m e r2 e e jr e r hj 3 where is the dielectric constant. I, shirin ghaderi, certify that the work presented in this thesis is my own. Quantum dots are tiny particles or nanocrystals of a semiconducting material with diameters in the range of 210 nanometers 1050 atoms. Inkjetprinted quantum dot hybrid lightemitting devices. Ultrafast dynamics in semiconductor quantum wells contains no material which has been accepted.
Quantum dots qds are a critical class of nanomaterials due to their unique properties, which include optical. This thesis presents an efficient method for cancer cell capture via cell linespecific antibody deposition and adsorption on nanoporous silica substrates using a method called microcontact printing and immunofluorescence detection through quantum dot labeling within a microfluidic system. The book quantum dots theory and applications collects some new research results in the area of fundamental excitations, decoherence, charge states, epitaxial techniques and photoluminescence experiments related to devices made with quantum dots. Semiconductor quantum dots are attractive building blocks for scalable quantum information processing systems. Doctoral thesis, nanyang technological university, singapore.
The essential elements for the synthesis of quantum dots involve combining an appropriate metallic, or organometallic precursors such as zinc, cadmium or mercury species with a corresponding chalcogen precursor such as sulfur, selenium or tellurium species in coordinating organic solvent at high temperatures. I declaration i declare that the work contained in this thesis submitted by me for the degree of master of science by research is my own work, except where due reference is made to other. The future looks bright and exciting on all the possible applications of quantum dots. Young thesis submitted in partial fulfillment of the requirements for the degree of master of science in electrical and computer engineering. The spinup and spindown states of a single electon, trapped inside a quantum dot, form a single quantum bit qubit with a long decoherence time.
Quantum dots qds, nanocarriers for drugs, can help realize the targeting of drugs, and improve the bioavailability of drugs in biological fields. A quantum dot is very small crystal of semiconductor materials whose excitons undergoes quantum conferment in three spatial dimensions and thus composed of about a hundred to a few thousand atoms. This thesis comprises works on novel quantum dot structures. Because of this smaller size they are called zero dimensional materials. Therefore, a practical class was developed to demonstrate quantum.
Charge sensing and spin dynamics in gaas quantum dots. Therefore, a practical class was developed to demonstrate quantum phenomena using cheap and safe chemical products. This book deals with the electronic and optical properties of two lowdimensional systems. Graduate thesis or dissertation synthesis, surface. Synthesis of quantum dots quantum dots sensor coursera. Root, major professor robert benjamin, committee member heather conradwebb, committee member arthur j. Multiphoton generation from a single quantum dot in a photonic. Nevertheless, prior stms studies have focused primarily on the structural2,3,4,5,6 or the spectroscopic characteristics,7,8,9,10,11,12, with a complete determination of qd size, shape, composition, and electronic properties based solely on stms having not been.
1382 1124 932 197 107 1229 340 819 379 264 328 1335 854 383 885 1068 1035 250 854 246 1382 1513 676 1097 12 1345 562 542 1458