Journal ArticleDOI
Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes
Patrick Waltereit,Oliver Brandt,Achim Trampert,Holger T. Grahn,J. Menniger,Manfred Ramsteiner,M. Reiche,Klaus H. Ploog +7 more
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TLDR
It is demonstrated that the epitaxial growth of GaN/(Al,Ga)N on tetragonal LiAlO2 in a non-polar direction allows the fabrication of structures free of electrostatic fields, resulting in an improved quantum efficiency, which is expected to pave the way towards highly efficient white LEDs.Abstract:
Compact solid-state lamps based on light-emitting diodes (LEDs) are of current technological interest as an alternative to conventional light bulbs The brightest LEDs available so far emit red light and exhibit higher luminous efficiency than fluorescent lamps If this luminous efficiency could be transferred to white LEDs, power consumption would be dramatically reduced, with great economic and ecological consequences But the luminous efficiency of existing white LEDs is still very low, owing to the presence of electrostatic fields within the active layers These fields are generated by the spontaneous and piezoelectric polarization along the [0001] axis of hexagonal group-III nitrides--the commonly used materials for light generation Unfortunately, as this crystallographic orientation corresponds to the natural growth direction of these materials deposited on currently available substrates Here we demonstrate that the epitaxial growth of GaN/(Al,Ga)N on tetragonal LiAlO2 in a non-polar direction allows the fabrication of structures free of electrostatic fields, resulting in an improved quantum efficiency We expect that this approach will pave the way towards highly efficient white LEDsread more
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Prospects for LED lighting
TL;DR: More than one-fifth of US electricity is used to power artificial lighting as discussed by the authors and light-emitting diodes based on group III/nitride semiconductors are bringing about a revolution in energy-efficient lighting.
Journal ArticleDOI
Perovskite light-emitting diodes based on spontaneously formed submicrometre-scale structures
Yu Cao,Nana Wang,He Tian,Jingshu Guo,Yingqiang Wei,Hong Chen,Yanfeng Miao,Wei Zou,Kang Pan,Yarong He,Hui Cao,You Ke,Mengmeng Xu,Ying Wang,Ming Yang,Kai Du,Zewu Fu,Decheng Kong,Daoxin Dai,Yizheng Jin,Gongqiang Li,Hai Li,Qiming Peng,Jianpu Wang,Wei Huang,Wei Huang,Wei Huang +26 more
TL;DR: The formation of submicrometre-scale structure in perovskite light-emitting diodes can raise their external quantum efficiency beyond 20%, suggesting the possibility of both high efficiency and high brightness.
Journal ArticleDOI
X-ray diffraction of III-nitrides
Michelle A. Moram,M E Vickers +1 more
TL;DR: In this article, the basic principles of x-ray diffraction of thin films and areas of special current interest, such as analysis of non-polar, semipolar and cubic III-nitrides, are reviewed, along with the basic principle of X-ray diffusion of thin thin films, and some useful values needed in calculations, including elastic constants and lattice parameters.
Journal ArticleDOI
Ultraviolet light-emitting diodes based on group three nitrides
TL;DR: In this paper, a light-emitting diodes with emission wavelengths less than 400 nm have been developed using the AlInGaN material system, where alloy compositions with a greater aluminium content are required.
Journal ArticleDOI
LEDs for Solid-State Lighting: Performance Challenges and Recent Advances
TL;DR: In this paper, the authors review LED performance targets that are needed to achieve these benefits and highlight some of the remaining technical challenges, and describe recent advances in LED materials and novel device concepts that show promise for realizing the full potential of LED-based white lighting.
References
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Journal ArticleDOI
Spontaneous polarization and piezoelectric constants of III-V nitrides
TL;DR: In this paper, the spontaneous polarization, dynamical Born charges, and piezoelectric constants of the III-V nitrides AlN, GaN, and InN are studied ab initio using the Berry-phase approach to polarization in solids.
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Nitride-based semiconductors for blue and green light-emitting devices
Fernando Ponce,David P. Bour +1 more
TL;DR: In this article, the group III elements of the semiconducting nitrides have been used for the fabrication of high-efficiency solid-state devices that emit green and blue light.
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30% external quantum efficiency from surface textured, thin‐film light‐emitting diodes
TL;DR: In this article, the authors showed that by separating thin-film LEDs from their substrates (by epitaxial lift-off, for example), it is much easier for light to escape from the LED structure and thereby avoid absorption.
Journal ArticleDOI
Effects of macroscopic polarization in III-V nitride multiple quantum wells
Vincenzo Fiorentini,Vincenzo Fiorentini,Fabio Bernardini,Fabio Della Sala,Aldo Di Carlo,Paolo Lugli +5 more
TL;DR: In this article, the authors discuss the background theory, role of spontaneous polarization in this context, and the practical implications of built-in polarization fields in nitride nanostructures.