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Author: Jason Paul Clifford
Publisher:
ISBN: 9780494579725
Category :
Languages : en
Pages : 398
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Book Description
Herein, we report the first solution-processed broadband photodetectors to break the past compromise between sensitivity and speed of response. Specifically, we report photodiodes having normalized detectivity (D*) > 1012 Jones and a 3dB bandwidth of > 2.9 MHz. This finding represents a 170,000 fold improvement in response speed over the most sensitive colloidal quantum dot (CQD) photodetector reported1 and a 100,000 fold improvement in sensitivity over the fastest CQD photodetector reported2.Efficient, sensitive semiconductor photodiodes are based on two fundamental characteristics: a large built-in potential that separates photogenerated charge carriers and minimizes internal noise generation, and high semiconductor conductivity for efficient collection of photogenerated charge. Schottky barriers to CQD films were developed to provide high, uniform built-in potentials. A multi-step CQD ligand exchange procedure was developed to allow deposition of tightly packed films of CQDs with high mobility and sufficiently well-passivated surfaces to form high-quality metallurgical junctions.The temporal response of the CQD photodiodes showed separate drift and diffusion components. Combined with detailed measurements of the Schottky barrier, these characteristics provided the physical basis for a numerical model of device operation. Based on this understanding, devices that excluded the slow diffusive component were fabricated, exploiting only the sub-microsecond field-driven transient to achieve MHz response bandwidth.At the outset of this study, sensitive, solution-processed IR photodetectors were severely limited by low response speeds1. Much faster response speeds had been demonstrated by solution-processed photodetectors operating in the visible3, but these devices offered no benefits for extending the spectral sensitivity of silicon. No available solution-processed photodetector combined high sensitivity, high operating speed, and response to illumination across the UV, visible and IR.We developed a fast, sensitive, solution-processed photodetector based on a photodiode formed by a Schottky barrier to a CQD film. Previous attempts to form sensitive photodetectors based on CQD photodiodes had demonstrated low quantum efficiencies that limited sensitivity4,5.These devices are the first to combine megahertz-bandwidth, high sensitivity, and spectral-tunability in photodetectors based on semiconducting CQDs. Record performance is achieved through advances in materials and device architecture based on a detailed understanding the physical mechanisms underlying the operation of CQD photodiodes.
Author: Jason Paul Clifford
Publisher:
ISBN: 9780494579725
Category :
Languages : en
Pages : 398
Get Book Here
Book Description
Herein, we report the first solution-processed broadband photodetectors to break the past compromise between sensitivity and speed of response. Specifically, we report photodiodes having normalized detectivity (D*) > 1012 Jones and a 3dB bandwidth of > 2.9 MHz. This finding represents a 170,000 fold improvement in response speed over the most sensitive colloidal quantum dot (CQD) photodetector reported1 and a 100,000 fold improvement in sensitivity over the fastest CQD photodetector reported2.Efficient, sensitive semiconductor photodiodes are based on two fundamental characteristics: a large built-in potential that separates photogenerated charge carriers and minimizes internal noise generation, and high semiconductor conductivity for efficient collection of photogenerated charge. Schottky barriers to CQD films were developed to provide high, uniform built-in potentials. A multi-step CQD ligand exchange procedure was developed to allow deposition of tightly packed films of CQDs with high mobility and sufficiently well-passivated surfaces to form high-quality metallurgical junctions.The temporal response of the CQD photodiodes showed separate drift and diffusion components. Combined with detailed measurements of the Schottky barrier, these characteristics provided the physical basis for a numerical model of device operation. Based on this understanding, devices that excluded the slow diffusive component were fabricated, exploiting only the sub-microsecond field-driven transient to achieve MHz response bandwidth.At the outset of this study, sensitive, solution-processed IR photodetectors were severely limited by low response speeds1. Much faster response speeds had been demonstrated by solution-processed photodetectors operating in the visible3, but these devices offered no benefits for extending the spectral sensitivity of silicon. No available solution-processed photodetector combined high sensitivity, high operating speed, and response to illumination across the UV, visible and IR.We developed a fast, sensitive, solution-processed photodetector based on a photodiode formed by a Schottky barrier to a CQD film. Previous attempts to form sensitive photodetectors based on CQD photodiodes had demonstrated low quantum efficiencies that limited sensitivity4,5.These devices are the first to combine megahertz-bandwidth, high sensitivity, and spectral-tunability in photodetectors based on semiconducting CQDs. Record performance is achieved through advances in materials and device architecture based on a detailed understanding the physical mechanisms underlying the operation of CQD photodiodes.
Author: Jason Paul Clifford
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Xin Tong
Publisher: Springer Nature
ISBN: 3030742709
Category : Technology & Engineering
Languages : en
Pages : 319
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Book Description
This book presents a comprehensive overview of state-of-the-art quantum dot photodetectors, including device fabrication technologies, optical engineering/manipulation strategies, and emerging photodetectors with building blocks of novel quantum dots (e.g. perovskite) as well as their hybrid structured (e.g. 0D/2D) materials. Semiconductor quantum dots have attracted much attention due to their unique quantum confinement effect, which allows for the facile tuning of optical properties that are promising for next-generation optoelectronic applications. Among these remarkable properties are large absorption coefficient, high photosensitivity, and tunable optical spectrum from ultraviolet/visible to infrared region, all of which are very attractive and favorable for photodetection applications. The book covers both fundamental and frontier research in order to stimulate readers' interests in developing novel ideas for semiconductor photodetectors at the center of future developments in materials science, nanofabrication technology and device commercialization. The book provides a knowledge sharing platform and can be used as a reference for researchers working in the fields of photonics, materials science, and nanodevices.
Author: Gerasimos Konstantatos
Publisher: Cambridge University Press
ISBN: 1107469368
Category : Technology & Engineering
Languages : en
Pages : 478
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Book Description
Capturing the most up-to-date research in colloidal quantum dot (CQD) devices, this book is written in an accessible style by the world's leading experts. The application of CQDs in solar cells, photodetectors and light-emitting diodes (LEDs) has developed rapidly over recent years, promising to transform the future of clean energy, communications, and displays. This complete guide to the field provides researchers, students and practitioners alike with everything they need to understand these developments and begin contributing to future applications. Introductory chapters summarise the fundamental physics and chemistry, whilst later chapters review the developments that have propelled the field forwards, systematically working through key device advances. The science of CQD films is explained through the latest physical models of semiconductor transport, trapping and recombination, whilst the engineering of organic and inorganic multilayered materials is shown to have enabled major advances in the brightness and efficiency of CQD LEDs.
Author: Gerasimos Konstantatos
Publisher: Cambridge University Press
ISBN: 0521198267
Category : Science
Languages : en
Pages : 329
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Book Description
Captures the most up-to-date research in the field, written in an accessible style by the world's leading experts.
Author: Zhiming M. Wang
Publisher: Springer Science & Business Media
ISBN: 1461435706
Category : Science
Languages : en
Pages : 375
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Book Description
Quantum dots as nanomaterials have been extensively investigated in the past several decades from growth to characterization to applications. As the basis of future developments in the field, this book collects a series of state-of-the-art chapters on the current status of quantum dot devices and how these devices take advantage of quantum features. Written by 56 leading experts from 14 countries, the chapters cover numerous quantum dot applications, including lasers, LEDs, detectors, amplifiers, switches, transistors, and solar cells. Quantum Dot Devices is appropriate for researchers of all levels of experience with an interest in epitaxial and/or colloidal quantum dots. It provides the beginner with the necessary overview of this exciting field and those more experienced with a comprehensive reference source.
Author: Jingda Wu
Publisher:
ISBN:
Category :
Languages : en
Pages : 82
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Book Description
This thesis will outline a new way of fabricating flexible photodetectors. Solution-processable colloidal quantum dots (QDs, or nanocrystals(NCs)) are incorporated into cellulose structures to form a composite structure that can be used for photodetection. This enables new ways of device fabrication and also makes ultrathin, ultraflexible and even transparent optoelectronic devices possible. Inkjet printing with an office inkjet printer is introduced and applied towards PEDOT:PSS transparent electrode deposition. This offers a low cost method for material deposition. Flexible photoconductors are fabricated with these electrodes and CdSe quantum dot embedded tracing paper by utilizing the porous cellulose structure. Consistent photoresponse is achieved with such a structure under 550nm light illumination. After further realizing the shortcomings of tracing paper for its large thickness and low porosity, which both deteriorate the performance of these devices, natural plant-membranes are chosen as an alternative and offer superb properties for optoelectronic device fabrication. Visible-blind self-powered ultra-violet detectors are designed and fabricated with the incorporation of ZnO NCs on reed membrane. Schottky junction devices are fabricated with the use of gold and aluminum as the electrodes. Sub-second responses are observed at a bias of zero, which is superior than most of the flexible photoconductors in the literature. An external quantum efficiency of over 3% is discovered with the device at 350nm light illumination under zero bias. A great performance enhancement is also observed on the devices fabricated on reed membrane comparing to the ones on tracing paper. Nanofibrillated cellulose(NFC) can be readily used to fabricate transparent papers. ZnO NC-NFC composite structure is prepared and fabricated into ultrathin transparent papers with a thickness less than 1 micrometer. Self-powered Schottky photodiodes are fabricated on such papers and relatively fast response is observed at zero bias.
Author: Ronald G. Driggers
Publisher: CRC Press
ISBN: 9780824742522
Category : Science
Languages : en
Pages : 1100
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Book Description
Compiled by 330 of the most widely respected names in the electro-optical sciences, the Encyclopedia is destined to serve as the premiere guide in the field with nearly 2000 figures, 560 photographs, 260 tables, and 3800 equations. From astronomy to x-ray optics, this reference contains more than 230 vivid entries examining the most intriguing technological advances and perspectives from distinguished professionals around the globe. The contributors have selected topics of utmost importance in areas including digital image enhancement, biological modeling, biomedical spectroscopy, and ocean optics, providing thorough coverage of recent applications in this continually expanding field.
Author:
Publisher: Woodhead Publishing
ISBN: 1782424687
Category : Science
Languages : en
Pages : 551
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Book Description
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
Author: Antoni Rogalski
Publisher: CRC Press
ISBN: 1000204936
Category : Science
Languages : en
Pages : 265
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Book Description
2D Materials for Infrared and Terahertz Detectors provides an overview of the performance of emerging detector materials, while also offering, for the first time, a comparison with traditional materials used in the fabrication of infrared and terahertz detectors. Since the discovery of graphene, its applications to electronic and optoelectronic devices have been intensively researched. The extraordinary electronic and optical properties allow graphene and other 2D materials to be promising candidates for infrared (IR) and terahertz (THz) photodetectors, and yet it appears that the development of new detectors using these materials is still secondary to those using traditional materials. This book explores this phenomenon, as well as the advantages and disadvantages of using 2D materials. Special attention is directed toward the identification of the most-effective hybrid 2D materials in infrared and terahertz detectors, as well as future trends. Written by one of the world’s leading researchers in the field of IR optoelectronics, this book will be a must-read for researchers and graduate students in photodetectors and related fields. Features • Offers a comprehensive overview of the different types of 2D materials used in fabrication of IR and THz detectors, and includes their advantages/disadvantages • The first book to compare new detectors to a wide family of common, commercially available detectors that use traditional materials.
