Controlled Growth of GaN Columns and 3D Core-Shell LEDs by MOVPE PDF Download
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Author: Xue Wang
Publisher: Cuvillier Verlag
ISBN: 3736980000
Category : Science
Languages : en
Pages : 186
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Book Description
GaN three-dimensional columnar core-shell LEDs are considered to be one of the promising candidates for prospective solid state lighting. In comparison to conventional planar layer LEDs, columnar core-shell LEDs have many advantages. For instance, in a columnar GaN coreshell LED structure the InGaN/GaN MQW wraps around the column, therefore the light emitting area can be enormously increased. This is the main driving force behind the intense investigation of nanowire and micro-columnar LEDs. In addition, because of the increased area of the MQW, the internal quantum efficiency may be improved by a reduction of the local carrier density, mitigating the efficiency droop. Besides, due to the reduced influence of thermal and lattice mismatch between the substrate and columns, dislocation-free GaN column arrays can be achieved on large area substrates. The main contribution of the present work is the controlled growth of GaN columns and core-shell LEDs by metal-organic vapor-phase expitaxy. The growth conditions which lead to vertical growth of N-polar and Ga-polar GaN columns are systematically investigated. The causes of the vertical growth are explained by surface processes under appropriate conditions for both polarities. Quantitative discussions of growth kinetics of GaN columns are an important feature in this work. The difficulties and the strategies of the MQW and p-GaN shell growth on high aspect ratio GaN columns are presented in detail.
Author: Xue Wang
Publisher: Cuvillier Verlag
ISBN: 3736980000
Category : Science
Languages : en
Pages : 186
Get Book Here
Book Description
GaN three-dimensional columnar core-shell LEDs are considered to be one of the promising candidates for prospective solid state lighting. In comparison to conventional planar layer LEDs, columnar core-shell LEDs have many advantages. For instance, in a columnar GaN coreshell LED structure the InGaN/GaN MQW wraps around the column, therefore the light emitting area can be enormously increased. This is the main driving force behind the intense investigation of nanowire and micro-columnar LEDs. In addition, because of the increased area of the MQW, the internal quantum efficiency may be improved by a reduction of the local carrier density, mitigating the efficiency droop. Besides, due to the reduced influence of thermal and lattice mismatch between the substrate and columns, dislocation-free GaN column arrays can be achieved on large area substrates. The main contribution of the present work is the controlled growth of GaN columns and core-shell LEDs by metal-organic vapor-phase expitaxy. The growth conditions which lead to vertical growth of N-polar and Ga-polar GaN columns are systematically investigated. The causes of the vertical growth are explained by surface processes under appropriate conditions for both polarities. Quantitative discussions of growth kinetics of GaN columns are an important feature in this work. The difficulties and the strategies of the MQW and p-GaN shell growth on high aspect ratio GaN columns are presented in detail.
Author:
Publisher: Forschungszentrum Jülich
ISBN: 3893368701
Category :
Languages : en
Pages : 415
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Book Description
Author: Sorin Cristoloveanu
Publisher: World Scientific
ISBN: 9814541877
Category : Technology & Engineering
Languages : en
Pages : 273
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Book Description
Frontiers in Electronics includes the best papers of WOFE-11 invited by the Editors and down selected after the peer review process. This book is conceived to make available in the international arena extended versions of selected, high impact talks. The papers are divided into four sections: advanced terahertz and photonics devices; silicon and germanium on insulator and advanced CMOS and MOSHFETs; nanomaterials and nanodevices; wide band gap technology for high power and UV photonics.
Author: Jana Hartmann
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The three dimensional growth of GaN structures as a basis for the fabrication of 3D GaN core-shell LEDs has attracted substantial attention in the past years. GaN nanorods or microrods with high aspect ratios can be grown by selective area epitaxy on a GaN buffer through a SiOx mask. It has been found earlier that silane substantially initiates vertical growth, with the exact underlying mechanisms being still unclear. Here, the influence of silane on the 3D GaN column growth was investigated by performing detailed growth experiments in combination with a thorough surface analysis in order to get insight into these mechanisms. The vertical growth rate is significantly enhanced by high silane fluxes, whereas the saturation of growth rate with the time is reduced. Thus, homogenous GaN columns with an aspect ratio of more than 35 could be achieved. A thin Si-rich layer on the non-polar m-plane facets of the columns has been detected using a combination of transmission electron microscopy, energy dispersive X-ray spectroscopy and Auger electron spectroscopy. This layer is suggested to be the reason for the increase in growth rate, modifying the effective collection range of the species along the sidewalls, and preventing the lateral growth.
Author: J Arbiol
Publisher: Elsevier
ISBN: 1782422633
Category : Technology & Engineering
Languages : en
Pages : 573
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Book Description
Semiconductor nanowires promise to provide the building blocks for a new generation of nanoscale electronic and optoelectronic devices. Semiconductor Nanowires: Materials, Synthesis, Characterization and Applications covers advanced materials for nanowires, the growth and synthesis of semiconductor nanowires—including methods such as solution growth, MOVPE, MBE, and self-organization. Characterizing the properties of semiconductor nanowires is covered in chapters describing studies using TEM, SPM, and Raman scattering. Applications of semiconductor nanowires are discussed in chapters focusing on solar cells, battery electrodes, sensors, optoelectronics and biology. Explores a selection of advanced materials for semiconductor nanowires Outlines key techniques for the property assessment and characterization of semiconductor nanowires Covers a broad range of applications across a number of fields
Author: Jana Hartmann
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
GaN fins are 3D architectures elongated in one direction parallel to the substrate surface. They have the geometry of walls with a large height to width ratio as well as small footprints. When appropriate symmetry directions of the GaN buffer are used, the sidewalls are formed by non-polar {11-20} planes, making the fins particularly suitable for many device applications like LEDs, FETs, lasers, sensors or waveguides. The influence of growth parameters like temperature, pressure, V/III ratio and total precursor flow on the fin structures is analyzed. Based on these results, a 2-temperature-step-growth was developed, leading to fins with smooth side and top facets, fast vertical growth rates and good homogeneity along their length as well as over different mask patterns. For the core-shell growth of fin LED heterostructures, the 2-temperature-step-growth shows much smoother sidewalls and less crystal defects in the InGaN QW and p-GaN shell compared to structures with cores grown in just one step. Electroluminescence spectra of the 2-temperature-step-grown fin LED are demonstrated.
Author: M Razeghi
Publisher: Elsevier
ISBN: 9780080444260
Category : Science
Languages : en
Pages : 602
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Book Description
Tremendous progress has been made in the last few years in the growth, doping and processing technologies of the wide bandgap semiconductors. As a result, this class of materials now holds significant promis for semiconductor electronics in a broad range of applications. The principal driver for the current revival of interest in III-V Nitrides is their potential use in high power, high temperature, high frequency and optical devices resistant to radiation damage. This book provides a wide number of optoelectronic applications of III-V nitrides and covers the entire process from growth to devices and applications making it essential reading for those working in the semiconductors or microelectronics. Broad review of optoelectronic applications of III-V nitrides
Author: Peter YU
Publisher: Springer Science & Business Media
ISBN: 3540264752
Category : Technology & Engineering
Languages : en
Pages : 651
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Book Description
Excellent bridge between general solid-state physics textbook and research articles packed with providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors "The most striking feature of the book is its modern outlook ... provides a wonderful foundation. The most wonderful feature is its efficient style of exposition ... an excellent book." Physics Today "Presents the theoretical derivations carefully and in detail and gives thorough discussions of the experimental results it presents. This makes it an excellent textbook both for learners and for more experienced researchers wishing to check facts. I have enjoyed reading it and strongly recommend it as a text for anyone working with semiconductors ... I know of no better text ... I am sure most semiconductor physicists will find this book useful and I recommend it to them." Contemporary Physics Offers much new material: an extensive appendix about the important and by now well-established, deep center known as the DX center, additional problems and the solutions to over fifty of the problems at the end of the various chapters.
Author: Alfred Goldberg
Publisher: Office of the Secretary, Historical Offi
ISBN:
Category : Architecture
Languages : en
Pages : 330
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Book Description
The most comprehensive account to date of the 9/11 attack on the Pentagon and aftermath, this volume includes unprecedented details on the impact on the Pentagon building and personnel and the scope of the rescue, recovery, and caregiving effort. It features 32 pages of photographs and more than a dozen diagrams and illustrations not previously available.
Author: Dieter Bimberg
Publisher: Springer Science & Business Media
ISBN: 3540778993
Category : Technology & Engineering
Languages : en
Pages : 369
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Book Description
Reducing the size of a coherently grown semiconductor cluster in all three directions of space to a value below the de Broglie wavelength of a charge carrier leads to complete quantization of the energy levels, density of states, etc. Such “quantum dots” are more similar to giant atoms in a dielectric cage than to classical solids or semiconductors showing a dispersion of energy as a function of wavevector. Their electronic and optical properties depend strongly on their size and shape, i.e. on their geometry. By designing the geometry by controlling the growth of QDs, absolutely novel possibilities for material design leading to novel devices are opened. This multiauthor book written by world-wide recognized leaders of their particular fields and edited by the recipient of the Max-Born Award and Medal 2006 Professor Dieter Bimberg reports on the state of the art of the growing of quantum dots, the theory of self-organised growth, the theory of electronic and excitonic states, optical properties and transport in a variety of materials. It covers the subject from the early work beginning of the 1990s up to 2006. The topics addressed in the book are the focus of research in all leading semiconductor and optoelectronic device laboratories of the world.
