Quantum Dot Molecules

A quantum dot molecule (QDM) is composed of two or more closely spaced quantum dots or “artificial atoms.” In recent years, QDMs have received much attention as an emerging new artificial quantum system. The interesting and unique coupling and energy transfer processes between the “artificial atoms” could substantially extend the range of possible applications of quantum nanostructures. This book reviews recent advances in the exciting and rapidly growing field of QDMs via contributions from some of the most prominent researchers in this scientific community. The book explores many interesting topics such as the epitaxial growth of QDMs, spectroscopic characterization, and QDM transistors, and bridges between the fundamental physics of novel materials and device applications for future information technology. Both theoretical and experimental approaches are considered. Quantum Dot Molecules can be recommended for electrical engineering and materials science department courses on the science and design of advanced and future electronic and optoelectronic devices.

Semiconductor Quantum Dots presents an overview of the background and recent developments in the rapidly growing field of ultrasmall semiconductor microcrystallites, in which the carrier confinement is sufficiently strong to allow only quantized states of the electrons and holes. The main emphasis of this book is the theoretical analysis of the confinement induced modifications of the optical and electronic properties of quantum dots in comparison with extended materials. The book develops the theoretical background material for the analysis of carrier quantum-confinement effects, introduces the different confinement regimes for relative or center-of-mass motion quantization of the electron-hole-pairs, and gives an overview of the best approximation schemes for each regime. A detailed discussion of the carrier states in quantum dots is presented and surface polarization instabilities are analyzed, leading to the self-trapping of carriers near the surface of the dots. The influence of spin-orbit coupling on the quantum-confined carrier states is discussed. The linear and nonlinear optical properties of small and large quantum dots are studied in detail and the influence of the quantum-dot size distribution in many realistic samples is outlined. Phonons in quantum dots as well as the influence of external electric or magnetic fields are also discussed. Last but not least the recent developments dealing with regular systems of quantum dots are also reviewed. All things included, this is an important piece of work on semiconductor quantum dots not to be dismissed by serious researchers and physicists. Contents: IntroductionTheoretical Concepts, Quantum Confinement RegimesElectron-Hole-Pair StatesOptical Properties of Small DotsOptical Properties of Large DotsPhonons and External FieldsCoupled Quantum DotsAppendix: Asymptotic Cluster Growth Laws Readership: Condensed matter physicists, researchers in laser and optical science. keywords:Absorption;Configuration Interaction;Confinement Energy;Excitons;Biexcitons;Confinement Regime;Spin-Orbit Coupling;Angular Momentum

The book provides a thorough survey of current research in quantum dots synthesis, properties, and applications. The unique properties of these new nanomaterials offer multifunctional applications in such fields as photovoltaics, light-emitting diodes, field-effect transistors, lasers, photodetectors, solar cells, biomedical diagnostics and quantum computing. Keywords: Quantum Dots (QD), Photovoltaics, Light-emitting Diodes, Field-effect Transistors, Lasers, Photodetectors, Solar Cells, Biomedical Diagnostics, Quantum Computing, QD Synthesis, Carbon QDs, Graphene QDs, QD Sensors, Supercapacitors, Magnetic Quantum Dots, Cellular/Molecular Separation, Chromatographic Separation Column, Photostability, Luminescence of Carbon QDs, QD Materials for Water Treatment, Semiconductor Quantum Dots, QD Drug Delivery, Antibacterial Quantum Dots.

Quantum dots (QDs) are luminescent semiconductor nanocrystals with unique chemical and physical properties due to their size and highly compact structure. QDs were first proposed for use in luminescent concentrators to replace organic dye molecules. In this book, the interest is in taking advantage of the emission properties of QDS, which can be tuned by their size, resulting from quantum confinement. In addition, the book discusses the potential of QDs as contrast and therapeutic agents in the field of medicine.

Quantum Dots captures many diverse applications enabling utility in biological detection. Organized into five parts, the first two parts cover the use of QDs in imaging fixed and living cells (and tissues). Protocols are included for using QDs in routine as well as enabling applications. Part 3 shows early efforts aimed at using QDs in live animals. The final two parts demonstrate the versatility of QD technology in existing assay technology.

A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one manometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.

This book reflects the current status of theoretical and experimental research of graphene based nanostructures, in particular quantum dots, at a level accessible to young researchers, graduate students, experimentalists and theorists. It presents the current state of research of graphene quantum dots, a single or few monolayer thick islands of graphene. It introduces the reader to the electronic and optical properties of graphite, intercalated graphite and graphene, including Dirac fermions, Berry's phase associated with sublattices and valley degeneracy, covers single particle properties of graphene quantum dots, electron-electron interaction, magnetic properties and optical properties of gated graphene nanostructures. The electronic, optical and magnetic properties of the graphene quantum dots as a function of size, shape, type of edge and carrier density are considered. Special attention is paid to the understanding of edges and the emergence of edge states for zigzag edges. Atomistic tight binding and effective mass approaches to single particle calculations are performed. Furthermore, the theoretical and numerical treatment of electron-electron interactions at the mean-field, HF, DFT and configuration-interaction level is described in detail.