Micro Light Emitting Diode: Fabrication and Devices PDF Download

Author: Jong-Hyun Ahn
Publisher: Springer Nature
ISBN: 9811655057
Category : Science
Languages : en
Pages : 161

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Book Description
This book focuses on basic fundamental and applied aspects of micro-LED, ranging from chip fabrication to transfer technology, panel integration, and various applications in fields ranging from optics to electronics to and biomedicine. The focus includes the most recent developments, including the uses in large large-area display, VR/AR display, and biomedical applications. The book is intended as a reference for advanced students and researchers with backgrounds in optoelectronics and display technology. Micro-LEDs are thin, light-emitting diodes, which have attracted considerable research interest in the last few years. They exhibit a set of exceptional properties and unique optical, electrical, and mechanical behaviors of fundamental interest, with the capability to support a range of important exciting applications that cannot be easily addressed with other technologies. The content is divided into two parts to make the book approachable to readers of various backgrounds and interests. The first provides a detailed description with fundamental materials and production approaches and assembly/manufacturing strategies designed to target readers who seek an understanding ofof essential materials and production approaches and assembly/manufacturing strategies designed to target readers who want to understand the foundational aspects. The second provides detailed, comprehensive coverage of the wide range of device applications that have been achieved. This second part targets readers who seek a detailed account of the various applications that are enabled by micro-LEDs.

Author: Pengfei Tian
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
This thesis presents a systematic study of the fabrication, efficiency and applications of micro-pixelated III-nitride light emitting diodes (micro-LEDs). Efficiency droop studies of micro-LEDs and the development of new-types of micro-LEDs have been investigated. The size dependence and temperature dependence of micro-LED efficiency droop have been analysed, providing a deep understanding of efficiency droop issue for general lighting and also demonstrating the advantages of micro-LEDs to alleviate such efficiency droop. Micro-LEDs on flexible substrates have been fabricated, which combine the flexibility of soft substrates and the high efficiency of inorganic LEDs for potential applications in flexible displays, biomedicine, etc. In addition, micro-LEDs on Si substrates were also fabricated to reduce the micro-LED device fabrication cost. The size-dependent efficiency droop study demonstrates that the smaller micro-LEDs have more uniform current spreading, which causes their higher efficiency and higher thermal saturation current density. In addition, the temperature-dependent efficiency droop study shows that both the radiative and Auger recombination coefficients decrease with increasing temperature, and the temperature dependence of the radiative and Auger recombination coefficients is weaker at a higher current density. So micro-LEDs possess stabler temperature dependent efficiency when operating at a high current density. Flexible micro-LEDs have been fabricated using metal bonding and laser lift off techniques with only one transfer step. Also, the micro-LED arrays on Si substrates were developed for the first time, which have lower fabrication cost compared with micro-LEDs on sapphire substrates. The applications in micro-display and visible light communication have been demonstrated for both the devices above. This work suggests that employing micro-LED techniques is a way to improve LED efficiency for general lighting. With development of flexible micro-LEDs and reduced fabrication cost of micro-LEDs on Si substrates, the future applications of micro-LEDs are expected to be greatly expanded.

Author:
Publisher: Academic Press
ISBN: 0128230630
Category : Science
Languages : en
Pages : 412

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Book Description
MicroLEDs', Volume 106 is currently recognized as the ultimate display technology and one of the fastest-growing technologies in the world as technology giants utilize it on a wide-ranging set of products. This volume combines contributions from MicroLED pioneers and world’s leading experts in the field who focus on the MicroLED development, current cutting-edge technologies of pursuing for realizing MicroLED large flat panel displays and televisions, virtual reality and 3D displays, light source for LI-FI data communications, neural interface and optogenetics, and future MicroLED technology trends. Contains contributions from original MicroLED inventors and pioneers Provides the most comprehensive and updated status of MicroLED technological advancements and applications Updates on future MicroLED technology trends

Author: Shengjun Zhou
Publisher: Springer Nature
ISBN: 9811904367
Category : Science
Languages : en
Pages : 244

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Book Description
This book highlights state-of-the-art in III-nitrides-based light-emitting diodes (LEDs). Motivated by the application prospects in lighting, high-resolution display, and health & medicine, the book systematically introduces the physical fundamentals, epitaxial growth, and device fabrications of III-nitride-based LEDs. Important topics including the structures of chips, device reliability and measurements and the advances in mini and micro LEDs are also discussed. The book is completed with a decade of research experience of the author’s team in the design and fabrication of III-nitrides-based LEDs, presenting the novel achievements in the stress control of the large mismatch heterostructures, defect formation and inhibition mechanism of the heteroepitaxial growth, LED epitaxial technologies, and the fabrication of high-efficient flip-chip LEDs. The book comprises of a valuable reference source for researchers and professionals engaged in the research and development of III-nitrides-based LEDs.

Author: Seung Hwan Ko
Publisher: BoD – Books on Demand
ISBN: 9533072733
Category : Technology & Engineering
Languages : en
Pages : 336

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Book Description
This book contains a collection of latest research developments on Organic light emitting diodes (OLED). It is a promising new research area that has received a lot of attention in recent years. Here you will find interesting reports on cutting-edge science and technology related to materials, fabrication processes, and real device applications of OLEDs. I hope that the book will lead to systematization of OLED study, creation of new research field and further promotion of OLED technology for the bright future of our society.

Author: Mohsen Asad
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The research presented provides a systematic attempt to address the major challenges for the development of flexible micro-light-emitting diode (LED) displays. The feasibility of driving GaN-based micro-LEDs with a-Si:H-based thin-film transistors by using a thin-film bonding and transfer process was initially proposed. This approach was implemented to create an inverted pixel structure where the cathode of the LED is connected directly to the drain contact of the drive TFT resulting in a pixel circuit having more than 2× higher brightness compared to a standard pixel design. This "paste-and-cut" technique was further demonstrated for the development of flexible displays, enabling the study of the effect of mechanical strain and self-heating of the devices on plastic. Through a finite-element analysis, it was determined that the applied stress-induced strain near the quantum wells of the micro-LEDs are negligible for devices with diameters smaller than 20 microns. Thermal simulation of the LEDs on plastic revealed that a copper bond layer thicker than 600 nm can be used to alleviate self-heating effects of the micro-LEDs. Using these design parameters, micro-LED arrays with 20 micron diameter were integrated onto flexible substrates to validate the theoretical predictions. Further scaling of the LED size revealed substrate bending also tilts the direction of the LED structure, allowing further extraction of light. This effect was demonstrated using nanowire LEDs with a 250 nm diameter transferred onto plastic, where the light output could be enhanced by 2× through substrate bending. Finally, through the removal of bulk defect and surface states, fabrication of highly efficient micro-LEDs having > 400% increase in light output (compared to conventional diodes) was achieved. This outcome was accomplished through the removal of the defective buffer region adjacent to the active layers of the LED and minimization of the non-radiative recombination at the sidewalls. The former was accomplished through the removal of the buffer layer after separation of the LED from the process wafer while the latter is accomplished using a surround cathode gate electrode to deplete free carriers from the sidewall of the forward-biased LED. The resulting performance enhancements provided a basis for high-brightness flexible micro-LED displays developed in this dissertation.

Author: Malvin Carl Teich
Publisher: Google Books/Teich Consultants
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 416

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Book Description
LED Lighting is a self-contained and introductory-level book featuring a blend of theory and applications that thoroughly covers this important interdisciplinary area. Building on the underlying fields of optics, photonics, and vision science, it comprises four parts. PART I is devoted to fundamentals. The behavior of light is described in terms of rays, waves, and photons. Each of these approaches is best suited to a particular set of applications. The properties of blackbody radiation, thermal light, and incandescent light are derived and explained. The essentials of semiconductor physics are set forth, including the operation of junctions and heterojunctions, quantum wells and quantum dots, and organic and perovskite semiconductors. PART II deals with the generation of light in semiconductors, and details the operation and properties of III-V semiconductor devices (MQWLEDs and μLEDs), quantum-dot devices (QLEDs & WOLEDs), organic semiconductor devices (OLEDs, SMOLEDs, PLEDs, & WOLEDs), and perovskite devices (PeLEDs, PPeLEDs, QPeLEDs, & PeWLEDs). PART III focuses on vision and the perception of color, as well as on colorimetry. It delineates radiometric and photometric quantities as well as efficacy and efficiency measures. It relays the significance of metrics often encountered in LED lighting, including the color rendering index (CRI), color temperature (CT), correlated color temperature (CCT), and chromaticity diagram. PART IV is devoted to LED lighting, focusing on its history and salutary features, and on how this modern form of illumination is deployed. It describes the principal components used in LED lighting, including white phosphor-conversion LEDs, chip-on-board (COB) devices, color-mixing LEDs, hybrid devices, LED filaments, retrofit LED lamps, LED luminaires, and OLED light panels. It concludes with a discussion of smart lighting and connected lighting. Each chapter contains highlighted equations, color-coded figures, practical examples, and reading lists.

Author: Shuailong Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
III-nitride micro-pixellated light-emitting diodes (micro-LEDs) are a novel format of light source capable of generating micro-scale, spatially and temporally-controllable light patterns. These devices consist of arrays of LED pixels with diameters in the range of 1 μm to 100 μm and emit light across the ultraviolet-blue-green-red part of the spectrum. In addition, compared with conventional broad-area LED devices, micro-LEDs show improved device performance in many aspects, such as high output power densities and the capability to withstand high injection current densities. For these reasons, micro-LEDs allow the study of interesting LED properties in regimes not accessible to conventional broad-area LEDs and also a wide range of novel LED applications. The research work presented in this thesis focuses on the novel applications of micro-LEDs in visible light communications (VLC) and micro-displays. Due to a reduced current crowding effect and superior thermal management capabilities, micro-LEDs can be driven at very high current densities, resulting in high modulation bandwidths of the devices. For this reason, optical data transmission was demonstrated from individual micro-LED pixels at bit rates of up to 1 Gbit/s using a high-speed probe under a binary amplitude modulation scheme. To make a more practical VLC system, micro-LED devices were integrated with specifically-designed complementary metaloxide-semiconductor (CMOS) electronics, which allow individual micro-LED pixels to be conveniently controlled via a simple computer interface. Such CMOS-controlled micro-LED devices have been demonstrated for data transmission at bit rates of up to 512 Mbit/s by modulating a single CMOS/micro-LED pixel and 1.5 Gbit/s by modulating four CMOS/micro-LED pixels simultaneously. Apart from the application in VLC, CMOS-controlled micro-LED devices can also be used to implement micro-display systems. A colour-tunable micro-display system capable of delivering high-resolution microscale dynamic images and tuning its colour from red to green has been demonstrated based on new LED epitaxial LED structures, micro-LED fabrication, and the CMOS technology. Other work reported in this thesis includes using micro-LEDs for data transmission in plastic optical fibre and investigating the modulation characteristics of colour-converters such as colloidal quantum dots and light-emitting polymer. A detailed study on size-dependent capacitance in III-nitride micro-LEDs, especially the negative capacitance (NC) effect, has also been reported in this thesis. This capacitance research sheds light on the mechanisms underlying the NC effect and is potentially useful for improving the LED performance for VLC and other applications.

Author: Jinmin Li
Publisher: Springer
ISBN: 3319992112
Category : Technology & Engineering
Languages : en
Pages : 601

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Book Description
Comprehensive in scope, this book covers the latest progresses of theories, technologies and applications of LEDs based on III-V semiconductor materials, such as basic material physics, key device issues (homoepitaxy and heteroepitaxy of the materials on different substrates, quantum efficiency and novel structures, and more), packaging, and system integration. The authors describe the latest developments of LEDs with spectra coverage from ultra-violet (UV) to the entire visible light wavelength. The major aspects of LEDs, such as material growth, chip structure, packaging, and reliability are covered, as well as emerging and novel applications beyond the general and conventional lightings. This book, written by leading authorities in the field, is indispensable reading for researchers and students working with semiconductors, optoelectronics, and optics. Addresses novel LED applications such as LEDs for healthcare and wellbeing, horticulture, and animal breeding; Editor and chapter authors are global leading experts from the scientific and industry communities, and their latest research findings and achievements are included; Foreword by Hiroshi Amano, one of the 2014 winners of the Nobel Prize in Physics for his work on light-emitting diodes.

Author: François Templier
Publisher: John Wiley & Sons
ISBN: 1119015065
Category : Technology & Engineering
Languages : en
Pages : 311

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Book Description
Microdisplays are displays requiring optical magnification and OLEDs (Organic Light-Emitting Diode) are self-emitting displays where each pixel includes a LED made of organic material, in general composed of small-molecule organic material. This title reviews in detail how OLED microdisplays are made as well as how they are used. All aspects from theory to application will be addressed: basic principles, display design, display fabrication, operation and performances, present and future applications. The book will be useful to anyone interested in this rapidly developing field, such as students or researchers, industry professionals (engineers, project leaders) in the field of display development/fabrication and display end-users.