Quantum Dot Heterostructures

Da die Nachfrage nach immer schnelleren und kleineren Halbleiterbauelementen stetig wächst, sind Quanten-Dots und -Pyramiden rasant in den Mittelpunkt der Halbleiterforschung gerückt. Dieses Buch vermittelt einen umfassenden Überblick über den aktuellen Forschungsstand auf diesem Gebiet. Behandelt werden u.a. Fragen, wie Strukturen aufgebaut, wie sie charakterisiert werden und wie sie die Leistungsfähigkeit der Bauelemente bestimmen. (11/98)

This book looks at the effects of ion implantation as an effective post-growth technique to improve the material properties, and ultimately, the device performance of In(Ga)As/GaAs quantum dot (QD) heterostructures. Over the past two decades, In(Ga)As/GaAs-based QD heterostructures have marked their superiority, particularly for application in lasers and photodetectors. Several in-situ and ex-situ techniques that improve material quality and device performance have already been reported. These techniques are necessary to maintain dot density and dot size uniformity in QD heterostructures and also to improve the material quality of heterostructures by removing defects from the system. While rapid thermal annealing, pulsed laser annealing and the hydrogen passivation technique have been popular as post-growth methods, ion implantation had not been explored largely as a post-growth method for improving the material properties of In(Ga)As/GaAs QD heterostructures. This work attempts to remedy this gap in the literature. The work also looks at introduction of a capping layer of quaternary alloy InAlGaAs over these In(Ga)As/GaAs QDs to achieve better QD characteristics. The contents of this volume will prove useful to researchers and professionals involved in the study of QDs and QD-based devices.

This book explores the effects of growth pause or ripening time on the properties of quantum dots(QDs). It covers the effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs. The effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs are discussed. The book offers insight into InAs/GaAs bilayer QD heterostructures with very thin spacer layers and discusses minimum spacer thickness required to grow electronically coupled bilayer QD heterostructures. These techniques make bilayer QD heterostructures a better choice over the single layer and uncoupled multilayer QD heterostructure. Finally, the book discusses sub-monolayer (SML) growth technique to grow QDs. This recent technique has been proven to improve the device performance significantly. The contents of this monograph will prove useful to researchers and professionals alike.

In this book, leading experts on quantum dot theory and technology provide comprehensive reviews of all aspects of quantum dot systems. The following topics are covered: (1) energy states in quantum dots, including the effects of strain and many-body effects; (2) self-assembly and self-ordering of quantum dots in semiconductor systems; (3) growth, structures, and optical properties of III-nitride quantum dots; (4) quantum dot lasers.

The book addresses issues associated with physics and technology of injection lasers based on self-organized quantum dots. Fundamental and technological aspects of quantum dot edge-emitting lasers and VCSELs, their current status and future prospects are summarized and reviewed. Basic principles of QD formation using self-organization phenomena are reviewed. Structural and optical properties of self-organized QDs are considered with a number of examples in different material systems. Recent achievements in controlling the QD properties including the effects of vertical stacking, changing the matrix bandgap and the surface density of QDs are reviewed. The authors focus on the use of self-organized quantum dots in laser structures, fabrication and characterization of edge and surface emitting diode lasers, their properties and optimization with special attention paid to the relationship between structural and electronic properties of QDs and laser characteristics. The threshold and power characteristics of the state-of-the-art QD lasers are demonstrated. Issues related to the long-wavelength (1.3-mm) lasers on a GaAs substrate are also addressed and recent results on InGaAsN-based diode lasers presented for the purpose of comparison.

This is an overview of different models and mechanisms developed to describe the capture and relaxation of carriers in quantum-dot systems. Despite their undisputed importance, the mechanisms leading to population and energy exchanges between a quantum dot and its environment are not yet fully understood. The authors develop a first-order approach to such effects, using elementary quantum mechanics and an introduction to the physics of semiconductors. The book results from a series of lectures given by the authors at the Master’s level.

This book describes the full range of possible strategies for laterally aligning self-assembled quantum dots on a substrate surface, beginning with pure self-ordering mechanisms and culminating with forced alignment by lithographic positioning. The text addresses both short- and long-range ordering phenomena and introduces future high integration of single quantum dot devices on a single chip. Contributions by well-known experts ensure that all relevant quantum-dot heterostructures are elucidated from diverse perspectives.

The book "Fingerprints in the optical and transport properties of quantum dots" provides novel and efficient methods for the calculation and investigating of the optical and transport properties of quantum dot systems. This book is divided into two sections. In section 1 includes ten chapters where novel optical properties are discussed. In section 2 involve eight chapters that investigate and model the most important effects of transport and electronics properties of quantum dot systems This is a collaborative book sharing and providing fundamental research such as the one conducted in Physics, Chemistry, Material Science, with a base text that could serve as a reference in research by presenting up-to-date research work on the field of quantum dot systems.