High-Performance Ultrafast Photodetectors


Book Description

This project concentrates on the design, fabrication and characterization of compound semiconductor photodetectors in various material systems operating at near-IR wavelengths. We utilize resonant cavity enhanced (RCE) detection scheme to optimize speed and responsivity of photodetectors. It is also desirable to combine multiple functions in a single photodetector structure. In addition to wavelength selectivity of RCE photodetectors, we have demonstrated that RCE detectors vertically integrated with one-pass detectors can be used for polarization sensing. We have fabricated RCE photodetectors working at 800 to 900 nm wavelength range with record bandwidth-efficiency products. RCE Schottky photodiodes with 100 GHz bandwidth, p-i-n photodiodes with 50 GHz bandwidth and near-unity quantum efficiency have been demonstrated.







Ultrafast High Power Photodetectors


Book Description

The goal of the proposed research is to develop new photodetectors that are capable of high power operation at high frequencies for microwave fiber optic link applications. Conventional high frequency photodetectors have low saturation power because of the small absorption volume required to reduce transit time and parasitic capacitance. We have proposed a novel velocity-matched distributed photodetector (VMDP) that can achieve high bandwidth and high saturation power simultaneously. During the performance period, we have successfully demonstrated three generations of long-wavelength VMDP's operating at 1.3 and 1.55 mm fiber optic communication wavelengths. The VMDP consisting of metal-semiconductor-metal (MSM) photodiodes serially connected by an optical core optical waveguide and an coplanar strip microwave transmission line that is velocity-matched to the optical waveguide. The MSM phodiodes have been patterned by both optical and e-beam lithography. We have demonstrated a bandwidth of 18 GHz and a quantum efficiency of 0.42 A/W. The maximum linear photocurrent measured is 12 mA. The distribution of photocurrents inside the VMDP has also been measured using a novel split contact structure. Test patterns on nanoscale MSM photodiodes show a bandwidth> 50 GHz (measurement limit). The research results achieved in this program has been transferred to TRW, Focused Research, and BAE. TRW has provided additional funding for transfer the technology to TRW. Focused Research has obtained a Phase II SBIR to commercialize VMDP.




High-Performance Carbon-Based Optoelectronic Nanodevices


Book Description

This book focuses on the photoelectric nanodevices based on carbon nanostructures, such as carbon nanotubes, graphene and related heterojunctions. The synthesis of carbon nanostructures and device fabrication are simply given. The interface charge transfer and the performance enhancement in the photodetectors and solar cells are comprehensively introduced. Importantly, carbon allotropes behave as high-mobility conductors or bandgap-tunable semiconductors depending on the atomic arrangements, the direct motivation is to fabricate all-carbon nanodevices using these carbon nanomaterials as building blocks. The photoelectric nanodevices based on all-carbon nanostructures have increasingly attracted attention in the future. The book offers a valuable reference guide to carbon-based photoelectric devices for researchers and graduate school students in the field. It will also benefit all researchers who investigate photoelectric nanodevices and photoelectric conversion with relevant frontier theories and concepts.







Ultrafast All-Optical Signal Processing Devices


Book Description

Semiconductor-based Ultra-Fast All-Optical Signal Processing Devices –a key technology for the next generation of ultrahigh bandwidth optical communication systems! The introduction of ultra-fast communication systems based on all-optical signal processing is considered to be one of the most promising ways to handle the rapidly increasing global communication traffic. Such systems will enable real time super-high definition moving pictures such as high reality TV-conference, remote diagnosis and surgery, cinema entertainment and many other applications with small power consumption. The key issue to realize such systems is to develop ultra-fast optical devices such as light sources, all-optical gates and wavelength converters. Ultra-Fast All-Optical Signal Processing Devices discusses the state of the art development of semiconductor-based ultrafast all-optical devices, and their various signal processing applications for bit-rates 100Gb/s to 1Tb/s. Ultra-Fast All-Optical Signal Processing Devices: Provides a thorough and in-depth treatment of the most recent achievements in ultrafast all-optical devices Discusses future networks with applications such as HD-TV and super-high definition moving screens as a motivating background for devices research Covers mode-locked semiconductor lasers, electro-absorption modulator based 160Gb/s signal sources, SOA based symmetric Mach-Zehnder type all-optical gates, intersubband transition gate device, and more Explains the technical issues behind turning the ultra-fast optical devices into practical working tools Examples of above 160Gb/s transmission experiments Discusses future prospects of the ultra-fast signal processing devices This invaluable reference will provide device researchers and engineers in industry, researchers at universities (including graduate students, and post doctorial researchers and professors) and research institutes with a thorough understanding of ultrahigh bandwidth optical communication systems. Device and communication market watchers will also find this book useful.




Ultrahigh-Speed Optical Transmission Technology


Book Description

This book is a detailed description of all the aspects of ultrahigh speed optical transmission technology. Ultrahigh-speed optical transmission technology is a key technology for increasing communication capacity. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.







Self-Assembly of Nanostructures


Book Description

This is the third volume in a series of books on selected topics in Nanoscale Science and Technology based on lectures given at the well-known Istituto Nazionale di Fisica Nucleare (INFN) schools of the same name. The present set of notes stems in particular from the participation and dedication of prestigious lecturers, such as Nunzio Motta, Fulvia Patella, Alexandr Toropov, and Anna Sgarlata. All lectures have been carefully edited and reworked, taking into account extensive follow-up discussions. A tutorial lecture by Motta et al. presents the analysis of the Poly(3-hexylthiophene) self assembly on carbon nanotubes and discusses how the interaction between the two materials forms a new hybrid nanostructure, with potential application to future solar cells technology. In their contribution, Patella et al. review quantum dots of III-V compounds, which offer appealing perspectives for more sophisticated applications in new generation devices such as single-photon emitters for nano-photonics and quantum computing. Focusing on self-assembled quantum dots, the chapter by Alexandr Toropov et al. provides a comprehensive review of some important aspects in the formation of quantum dots and presents the results of the authors’ extensive investigation of the features of droplet epitaxy. The fourth contribution, by Sgarlata et al., focuses on recent progress toward controlled growth of self-assembled nanostructures, dealing with the shaping, ordering and localization in Ge/Si heteroepitaxy and reviewing recent results on the self-organization of Ge nanostructures at Si surfaces.




Advances in Photodetectors


Book Description

This book provides a wide-ranging overview of the current state-of-the-art and new trends in photodetector design and research. Written by a team of internationally renowned experts, with contributions from universities, research institutes and industries, this work is suitable for students and professionals interested in studying and dealing with photodetector design and technology, as well as the wide gamut of related applications. Its coverage includes: physics and fundamentals of photodetectors; physical models of photodetector operation; new materials, design, processing and function of photodetectors in related applications; testing, monitoring and calibration; and research progress in photodetector-related areas. Theoretical aspects, design and simulation principles, and important experimental results are thoroughly addressed, embodying a comprehensive account of current activity in this important field of research and industry.