The exponential increase of the Internet of Things (IoTs) has revolutionized lives, but it has also resulted in massive resource consumption and environmental pollution. In conjunction with Green IoTs (GioTs), there is a parallel effort to create highly sensitive devices by device design to conserve power. Furthermore, numerous applications require deciphering information from very weak optical signals, such as from radiation, medical imaging, industrial non-destructive testing, quantum technologies, astronomy, and various other such routine measurements. It is necessary to design photodetectors with high photosensitivity using various technological innovations to reduce the noise level, such as with two inversely directed barriers, as proposed by the authors, in which the currents of devices mutually compensate each other and create low dark current with high photosensitivity thresholds. The implementation of internal amplification of photocurrents in them can provide high photosensitivity. The book presents the mechanism for the injection amplification of the photocurrent in devices based on cadmium telluride and silicon with a high-resistance sublayer, as well as the study of creating highly sensitive devices, that are resistant to radiation of optical and X-ray ranges of electromagnetic waves. Particular attention is drawn to the mutual compensation process for photocurrents arising in opposite potential barriers covering the layer during longitudinal absorption of radiation in the sublayer. Using structures on the base cadmium telluride and silicon, as an example, the phenomenon of a change in the sign of the spectral photocurrent and the possibilities of wave measurement is provided by this phenomenon. Photoelectronic processes occurring in these semiconductor structures are investigated, and expressions are obtained that relate the parameters of optical radiation and the structure. The algorithm developed using these expressions is based on a new spectral analysis mechanism, which is implemented to prepare inexpensive, reduced dimensions with the need for less materials, and energy-intensive devices. All this is considered in the context of solving urgent problems of quantitative remote identification of the components of an optically transparent medium. The global spectral analysis market is focused on the development of semiconductor photodetectors with spectral-selective sensitivity for spectral analysis. The use of such a photodetector in spectrometry will eliminate the use of opticalmechanical systems due to the new physical principle used in it and will ensure high resolution and reliability of spectrum recording. As environmental threats become increasingly unpredictable, there is also a growing need to develop remote spectral analysis, identification, and assessment of substances in air, water, and food, assessment of the effects of substances on humans, animals, and vegetation, and detection and elimination of pollution sources. Here, the spectral analysis of the electromagnetic radiation transmitting the information from the object with the help of primary sensors is essential.

Every bit of information that circulates the internet across the globe is a pulse of light, that at some point will need to be converted to an electric signal in order to be processed by the electronic circuitry in our data centers, computers, and cell phones. Photodetectors (PD's) perform this conversion with ultra high speed and efficiency, in addition to being ubiquitously present in many other devices ranging from the mundane TV remote controls, to ultra high resolution instrumentation used in Laser Interferometer Gravitational Wave Observatory (LIGO) that reach the edge of the universe and measure gravitational waves. The second edition of "Photodetectors" fully updates the popular first edition with updated information covering the state-of-the-art in modern photodetectors. The 2nd edition starts with basic metrology of photodetectors and common figures-of-merit to compare various devices. It follows with chapters that discuss single-photon detection with Avalanche Photodiodes; organic photodetectors that can be inkjet printed; and silicon-germanium PDs popular in burgeoning field of Silicon Photonics. Internationally recognized experts contribute chapters on one-dimensional, nanowire, PDs as well as high speed zero-dimensional, quantum dot, versions that increase the spectral span as well as speed and sensitivity of PDs and can be produced on various substrates. Solar-blind PDs that operate in harsh environments such as deep space, or rocket engines, are reviewed and new devices in GaN technology . Novel Plasmonic PDs, as well as devices which employ micro-plasma of confined charge in order to make devices that overcome speed limitation of transfer of electronic charge, are covered in other chapters. Using different, novel technologies, CMOS compatible devices are described in two chapters, and ultra high speed PDs that use low-temperature-grown GaAs (LT-GaAs) to detect fast THz signals are reviewed in another chapter. Photodetectors used in application areas of Silicon-Photonics and Microwave-Photonics are reviewed in final chapters of this book. All chapters are of a review nature, providing a perspective of the field before concentrating on particular advancements. As such, the book should appeal to a wide audience that ranges from those with general interest in the topic, to practitioners, graduate students and experts who are interested in the state-of-the-art in photodetection. - Addresses various photodetector devices from ultra high speed to ultra high sensitivity, capable of operation in harsh environments - Considers a range of applications for this important technology, including silicon photonics and photonic integrated circuits - Includes discussions of detectors based on reduced dimensional systems such as quantum wells, nanowires, and quantum dots, as well as travelling wave, and plasmonic detectors

Semiconductor sensors patterned at the micron scale combined with custom-designed integrated circuits have revolutionized semiconductor radiation detector systems. Designs covering many square meters with millions of signal channels are now commonplace in high-energy physics and the technology is finding its way into many other fields, ranging from astrophysics to experiments at synchrotron light sources and medical imaging. This book is the first to present a comprehensive discussion of the many facets of highly integrated semiconductor detector systems, covering sensors, signal processing, transistors and circuits, low-noise electronics, and radiation effects. The diversity of design approaches is illustrated in a chapter describing systems in high-energy physics, astronomy, and astrophysics. Finally a chapter "Why things don't work" discusses common pitfalls. Profusely illustrated, this book provides a unique reference in a key area of modern science.

In this monograph, investigations of the performance of narrow-gap semiconductor photodiodes are presented, and recent progress in different IR photodiode technologies is discussed: HgCdTe photodiodes, InSb photodiodes, alternatives to HgCdTe III-V and II-VI ternary alloy photodiodes, lead chalcogenide photodiodes, and a new class of photodiodes based on two-dimensional solids. Investigations of the performance of photodiodes operated in different spectral regions are presented.

Explore this comprehensive introduction to the foundations of photodetection from one of the leading voices in the field The newly revised Photodetectors: Devices, Circuits and Applications delivers a thoroughly updated exploration of the fundamentals of photodetection and the novel technologies and concepts that have arisen since the release of the first edition twenty years ago. The book offers discussions of established and emerging photodetection technologies, including photomultipliers, the SPAD, the SiPM, the SNSPD, the UTC, the WGPD/TWPD, the QWIP, and the LT-GaAs. New examinations of correlation measurements on ultrafast pulses and single-photon detectors for quantum communications and LiDARs have also been added. Each chapter includes selected problems for students to work through to aid in learning and retention. A booklet of solutions is also provided. The book is especially ideal for students and faculties of Engineering, with an emphasis on first principles, design, and the engineering of photodetectors. Issues in the book are grouped through the development of concepts, as opposed to collections of technical details. Perfect for undergraduate students interested in the science or design of modern optoelectronics, Photodetectors: Devices, Circuits and Applications also belongs on the bookshelves of professors teaching PhD seminars in advanced courses on photodetection and noise, as well as engineers and physicists seeking a guide to an optimum photodetection solution.

Photodetectors and Fiber Optics is an outgrowth of the recently published 10-volume set Handbook of Advanced Electronic and Photonic Materials and Devices. The objective of this book is to present a highly coherent coverage of photodetectors and optical fibers. This book overs a broad spectrum of photodetectors, including types of materials, their fabrication, physical properties, and industrial applications. Many industries around the world are engaged in developing fiber optics technology for the new millennium. The applications of photodetectors in fiber optics and the role of optical fibers in present communication technology are extensively discussed. - Covers a broad spectrum of the photodetectors - Include types of materials, their fabrication, physical properties and industrial applications - Applications of photodetectors in fiber optics - Role of optical fibers in present communication technology - A very special topic presented in a timely manner and in a format