Silicon (Si) technologies provide an excellent platform for the design of microsystems where photonic and microelectronic functionalities are monolithically integrated on the same substrate. In recent years, a variety of passive and active Si photonic devices have been developed, and among them, photodetectors have attracted particular interest from the scientific community. Si photodiodes are typically designed to operate at visible wavelengths, but, unfortunately, their employment in the infrared (IR) range is limited due to the neglectable Si absorption over 1100 nm, even though the use of germanium (Ge) grown on Si has historically allowed operations to be extended up to 1550 nm. In recent years, significant progress has been achieved both by improving the performance of Si-based photodetectors in the visible range and by extending their operation to infrared wavelengths. Near-infrared (NIR) SiGe photodetectors have been demonstrated to have a “zero change” CMOS process flow, while the investigation of new effects and structures has shown that an all-Si approach could be a viable option to construct devices comparable with Ge technology. In addition, the capability to integrate new emerging 2D and 3D materials with Si, together with the capability of manufacturing devices at the nanometric scale, has led to the development of new device families with unexpected performance. Accordingly, this Special Issue of Micromachines seeks to showcase research papers, short communications, and review articles that show the most recent advances in the field of silicon photodetectors and their respective applications.

Optical Interconnects in Future Data Center Networks covers optical networks and how they can be used to provide high bandwidth, energy efficient interconnects for future data centers with increased communication bandwidth requirements. This contributed volume presents an integrated view of the future requirements of the data centers and serves as a reference work for some of the most advanced solutions that have been proposed by major universities and companies. Collecting the most recent and innovative optical interconnects for data center networks that have been presented in the research community by universities and industries, this book is a valuable reference to researchers, students, professors and engineers interested in the domain of high performance interconnects and data center networks. Additionally, Optical Interconnects in Future Data Center Networks provides invaluable insights into the benefits and advantages of optical interconnects and how they can be a promising alternative for future data center networks.

To keep pace with the scaling of semiconductor technology, the amount of energy required to transmit one bit of information needs to be drastically reduced. Optical interconnects may become a key technology in enabling high bandwidth interconnections, provided that its components operate at sufficiently low energies per bit. At the receiver, the capacitance of the photodetector limits the speed and power consumption that can be achieved. Lower capacitance can be achieved by reducing the physical size of the photodetector to nanoscale volumes, an order of magnitude smaller than the optical wavelength. This dissertation focuses on metallic nanostructures that can be used to bridge this size mismatch between the optical mode and the optoelectronic device. They can be used to enhance the interaction between the optical signal and the photodetector, and if designed as a waveguiding structure, they can provide an efficient way of routing optical signals with deep subwavelength mode dimensions and can integrate well with nanoscale photodetectors, providing a route towards highly integrated low capacitance detectors for optical interconnects.

Photodetectors: Materials, Devices and Applications discusses the devices that convert light to electrical signals, key components in communication, computation, and imaging systems. In recent years, there has been significant improvement in photodetector performance, and this important book reviews some of the key advances in the field. Part one covers materials, detector types, and devices, and includes discussion of silicon photonics, detectors based on reduced dimensional charge systems, carbon nanotubes, graphene, nanowires, low-temperature grown gallium arsenide, plasmonic, Si photomultiplier tubes, and organic photodetectors, while part two focuses on important applications of photodetectors, including microwave photonics, communications, high-speed single photon detection, THz detection, resonant cavity enhanced photodetection, photo-capacitors and imaging. Reviews materials, detector types and devices Addresses fabrication techniques, and the advantages and limitations and different types of photodetector Considers a range of application for this important technology Includes discussions of silicon photonics, detectors based on reduced dimensional charge systems, carbon nanotubes, graphene, nanowires, and more

Optical Interconnects provides a fascinating picture of the state of the art in optical interconnects and a perspective on what can be expected in the near future. It is composed of selected reviews authored by world leaders in the field, and these reviews are written from either an academic or industrial viewpoint. An in-depth discussion of the path towards fully-integrated optical interconnects in microelectronics is presented. This book will be useful not only to physicists, chemists, materials scientists, and engineers but also to graduate students who are interested in the fields of microelectronics and optoelectronics.