The on-chip interconnect bandwidth limitation is becoming an increasingly critical challenge for integrated circuits (ICs) as device scaling continues to push the speed and density of ICs. Silicon photonics has the ability to solve this emerging problem due to its high speed, high bandwidth, low power consumption, and ability to be monolithically integrated on silicon. Most of the key devices for Si photonic ICs have already been demonstrated. However, a practical CMOS compatible coherent light source is still a major challenge. Germanium (Ge) has already been demonstrated to be a promising material for optoelectronic devices, such as photo-detectors and modulators. However, Ge is an indirect band gap semiconductor, which makes Ge-based light sources very inefficient and limits their practical use. Fortunately, the direct [uppercase Gamma] valley of the Ge conduction band is only 0.14 eV higher than the indirect L valley, suggesting that with band-structure engineering, Ge has the potential to become a direct band gap material and an efficient light emitter. In this dissertation, we first discuss our work on highly biaxial tensile strained Ge grown by molecular beam epitaxy (MBE). Relaxed step-graded InGaAs buffer layers, which are prepared with low temperature growth and high temperature annealing, are used to provide a larger lattice constant substrate to produce tensile strain in Ge epitaxial layers. Up to 2.3% in-plane biaxial tensile strained thin Ge epitaxial layers were achieved with smooth surfaces and low threading dislocation density. A strong increase of photoluminescence with highly tensile strained Ge layers at low temperature suggests that a direct band gap semiconductor has been achieved. This dissertation also presents our work on more than 9% Sn incorporation in epitaxial GeSn alloys using a low temperature MBE growth method. This amount of Sn is 10 times greater than the solid-solubility of Sn in crystalline Ge. Material characterization shows good crystalline quality without Sn precipitation or phase segregation. With increasing Sn percentage, direct band gap narrowing is observed by optical transmission measurements. The studies described in this dissertation will help enable efficient germanium based CMOS compatible coherent light sources. Other possible applications of this work are also discussed in the concluding chapter.

Advanced semiconductor technology is depending on innovation and less on "classical" scaling. SiGe, Ge, and Related Compounds has become a key component in the arsenal in improving semiconductor performance. This symposium discusses the technology to form these materials, process them, FET devices incorporating them, Surfaces and Interfaces, Optoelectronic devices, and HBT devices.

Representing a further step towards enabling the convergence of computing and communication, this handbook and reference treats germanium electronics and optics on an equal footing. Renowned experts paint the big picture, combining both introductory material and the latest results. The first part of the book introduces readers to the fundamental properties of germanium, such as band offsets, impurities, defects and surface structures, which determine the performance of germanium-based devices in conjunction with conventional silicon technology. The second part covers methods of preparing and processing germanium structures, including chemical and physical vapor deposition, condensation approaches and chemical etching. The third and largest part gives a broad overview of the applications of integrated germanium technology: waveguides, photodetectors, modulators, ring resonators, transistors and, prominently, light-emitting devices. An invaluable one-stop resource for both researchers and developers.

This book focuses on advances in materials science and device applications of nanostructures composed of Si, Ge, diamond, SiGe and SiCGe. Continuous progress in the development of reproducibly grown quantum dots, wires and wells has produced a new class of functional materials and devices with characteristic dimensions less than 50nm. The broad spectrum of these devices ranges from commercially offered high-mobility transistors using strained Si to exploratory SiGe nanostructures for integrated optical interconnects and THz lasers. This book brings together researchers from chemistry, physics, biology, materials science and engineering to share and discuss both the challenges and progress towards a new generation of Si(SiGe, SiCGe)-based novel functional structures and devices. Topics include: light emission and photonic devices; Ge, SiGe and diamond nanostructures; strains, Si/Ge films and layers and Si nanocrystals.

Mid-infrared Optoelectronics: Materials, Devices, and Applications addresses the new materials, devices and applications that have emerged over the last decade, along with exciting areas of research. Sections cover fundamentals, light sources, photodetectors, new approaches, and the application of mid-IR devices, with sections discussing LEDs, laser diodes, and quantum cascade lasers, mid-infrared optoelectronics, emerging research areas, dilute bismide and nitride alloys, Group-IV materials, gallium nitride heterostructures, and new nonlinear materials. Finally, the most relevant applications of mid-infrared devices are reviewed in industry, gas sensing, spectroscopy, and imaging. This book presents a key reference for materials scientists, engineers and professionals working in R&D in the area of semiconductors and optoelectronics. - Provides a comprehensive overview of mid-infrared photodetectors and light sources and the latest materials and devices - Reviews emerging areas of research in the field of mid-infrared optoelectronics, including new materials, such as wide bandgap materials, chalcogenides and new approaches, like heterogeneous integration - Includes information on the most relevant applications in industry, like gas sensing, spectroscopy and imaging

Photonic devices lie at the heart of the communications revolution, and have become a large and important part of the electronic engineering field, so much so that many colleges now treat this as a subject in its own right. With this in mind, the author has put together a unique textbook covering every major photonic device, and striking a careful balance between theoretical and practical concepts. The book assumes a basic knowledge of optics, semiconductors and electromagnetic waves. Many of the key background concepts are reviewed in the first chapter. Devices covered include optical fibers, couplers, electro-optic devices, magneto-optic devices, lasers and photodetectors. Problems are included at the end of each chapter and a solutions set is available. The book is ideal for senior undergraduate and graduate courses, but being device driven it is also an excellent engineers' reference.