Mid-infrared Semiconductor Optoelectronics

The mid-infrared (2-10µm) spectral region is of enormous scientific and technological interest because it contains the strongest fingerprint absorption bands of a number of pollutant and toxic gases which require monitoring in a variety of different situations (e.g., oil-rigs, coal mines, landfill sites and car exhausts) and in concentrations, ranging from parts per billion to almost 100%. Organic liquids, narcotics and many biological and bio-medical analytes also have fingerprint absorptions in this spectral range. In addition, the atmospheric transmission window between 3 µm and 5 µm enables free-space optical communications, thermal imaging and the development of infrared counter-measures for "homeland security". However, many of these applications require technology based on un-cooled, efficient, inexpensive sources and detectors which are not yet available and so wide exploitation of this spectral range has yet to take place. §There is no doubt that the practical realisation of mid-infrared semiconductor lasers, LEDs and detectors which can operate at room temperature will transform them from a specialist research curiosity to a pervasive technology that will unlock a wide variety of applications. Many of the necessary developments depend on the ability to fabricate suitable high-quality epitaxial materials through the use of strained-layer engineering at the nanoscale and to manipulate the optoelectronic properties of the corresponding quantum device structures. There are a number of different materials, active region designs and device structures currently being investigated for both light sources and detectors. Many of the salient features together with recent progress in each of these areas is presented in this text. §Mid-infrared Semiconductor Optoelectronics is an overview of the current status and technological advances in this rapidly developing area. It is divided into four parts. First, some of the basic physics and the main problems facing the device engineer (together with a comparison of possible solutions) are presented. Next, there is a consideration of the different types of lasers currently under development. For practical mid-infrared applications semiconductor lasers must operate at room temperature and several different approaches to achieve this, particularly within the difficult 3 4 µm spectral region are discussed. Part III reviews recent work on light-emitting diodes and photodetectors and also deals with negative luminescence. The final part of the book is concerned with applications and highlights, once more, the diversity and technological importance of the mid-infrared spectral region.§The text has been produced by a world-wide authorship of experts in mid-infrared physics and technology, each working at the cutting edge in their own specialist area. Mid-infrared Semiconductor Optoelectronics will be an invaluable reference for researchers and graduate students drawn from backgrounds in physics, electronic and electrical engineering and materials science. Its breadth and thoroughness also make it an excellent starting point for further research and investigation.Optoelectronic devices operating in the mid-infrared wavelength range offer applications in a variety of areas from environmental gas monitoring around oil rigs to the detection of narcotics. They could also be used for free-space optical communications, thermal imaging applications and the development of "homeland security" measures.§Mid-infrared Semiconductor Optoelectronics is an overview of the current status and technological development in this rapidly emerging area; the basic physics, some of the problems facing the design engineer and a comparison of possible solutions are laid out; the different lasers used as sources for mid-infrared technology are considered; recent work in detectors is reviewed; the last part of the book is concerned with applications.§With a world-wide authorship of experts working in many mid-infrared-related fields this book will be an invaluable reference for researchers and graduate students drawn from physics, electronic and electrical engineering and materials science.The practical realisation of optoelectronic devices operating in the 2 10 µm (mid-infrared) wavelength range offers potential applications in a variety of areas from environmental gas monitoring around oil rigs and landfill sites to the detection of pharmaceuticals, particularly narcotics. In addition, an atmospheric transmission window exists between 3 µm and 5 µm that enables free-space optical communications, thermal imaging applications and the development of infrared measures for "homeland security". Consequently, the mid-infrared is very attractive for the development of sensitive optical sensor instrumentation.§Unfortunately, the nature of the likely applications dictates stringent requirements in terms of laser operation, miniaturisation and cost that are difficult to meet. Many of the necessary improvements are linked to a better ability to fabricate and to understand the optoelectronic properties of suitable high-quality epitaxial materials and device structures. Substantial progress in these matters is presented here.§Mid-infrared Semiconductor Optoelectronics is an overview of the current status and technological development in this rapidly emerging area. It is composed of four parts. First, the basic physics and some of the main problems facing the design engineer (together with a comparison of possible solutions) are laid out. Next, there is a consideration of the multifarious lasers used as sources for mid-infrared technology, including an inspection of current approaches to the lack of such a source in the 3 4 µm region. Part III reviews recent work in light-emitting diodes and detectors and also deals with negative luminescence. The final part of the book is concerned with applications and highlights, once more, the diversity and technological importance of the mid-infrared spectral region.§With a world-wide authorship of experts working in a number of different mid-infrared-related fields Mid-infrared Semiconductor Optoelectronics will be an invaluable reference for researchers and graduate students drawn from backgrounds in physics, electronic and electrical engineering and materials science. Its breadth and thoroughness also make it an excellent starting point for further research and investigation.