Characterization of Hydride Vapor Phase Epitaxy Grown GaN Substrates for Future III-nitride Growth PDF Download
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Author: Alaa Ahmad Kawagy
Publisher:
ISBN:
Category : Epitaxy
Languages : en
Pages : 190
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Book Description
The aim of this research is to investigate and characterize the quality of commercially obtained gallium nitride (GaN) on sapphire substrates that have been grown using hydride vapor phase epitaxy (HVPE). GaN substrates are the best choice for optoelectronic applications because of their physical and electrical properties. Even though HVPE GaN substrates are available at low-cost and create the opportunities for growth and production, these substrates suffer from large macro-scale defects on the surface of the substrate. In this research, four GaN on sapphire substrates were investigated in order to characterize the surface defects and, subsequently, understand their influence on homoepitaxial GaN growth. Two substrates were unintentionally doped (UID) GaN on sapphire, and the other two were semi-insulating (SI) GaN on sapphire which were doped with iron (Fe) in order to compensate the background doping inherent in GaN. Several characterization techniques were performed. Atomic force microscopy, scanning electron microscopy, and optical microscopy were performed to characterize the surface morphology. X-ray diffraction, cathodoluminescence, transmission measurements, and optical transmission electron microscopy were applied to study the bulk structural and optical properties. The investigation of the surface of GaN substrates exposed various defects that are associated with defects in the structure such as dislocations, as well as vacancies and point defects. The UID GaN substrates suffered from hexagonal V-shape pits with pits densities of approximately 107 and 108 cm-2, whereas, the SI GaN substrates exhibited much larger macro-scale pits with areal densities of about 102 cm-2. X-ray diffraction results were deconvoluted in order to characterize the screw and mixed (edge and screw) dislocation densities for the studied substrates. The UID substrates exhibited screw dislocation densities of 107 and 108 cm-2 and mixed dislocation densities of 109 and 1010 cm-2. The SI substrates, however, exhibit generally lower densities of dislocations of 109 and 108 cm-2 for screw and mixed, respectively. Cathodoluminescence measurements demonstrated interesting results for the UID and SI substrates with energies of 4 and 3.5 eV, respectively. The transmission measurements for the UID substrates showed that the bandgap energy was 3.39 eV.
Author: Alaa Ahmad Kawagy
Publisher:
ISBN:
Category : Epitaxy
Languages : en
Pages : 190
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Book Description
The aim of this research is to investigate and characterize the quality of commercially obtained gallium nitride (GaN) on sapphire substrates that have been grown using hydride vapor phase epitaxy (HVPE). GaN substrates are the best choice for optoelectronic applications because of their physical and electrical properties. Even though HVPE GaN substrates are available at low-cost and create the opportunities for growth and production, these substrates suffer from large macro-scale defects on the surface of the substrate. In this research, four GaN on sapphire substrates were investigated in order to characterize the surface defects and, subsequently, understand their influence on homoepitaxial GaN growth. Two substrates were unintentionally doped (UID) GaN on sapphire, and the other two were semi-insulating (SI) GaN on sapphire which were doped with iron (Fe) in order to compensate the background doping inherent in GaN. Several characterization techniques were performed. Atomic force microscopy, scanning electron microscopy, and optical microscopy were performed to characterize the surface morphology. X-ray diffraction, cathodoluminescence, transmission measurements, and optical transmission electron microscopy were applied to study the bulk structural and optical properties. The investigation of the surface of GaN substrates exposed various defects that are associated with defects in the structure such as dislocations, as well as vacancies and point defects. The UID GaN substrates suffered from hexagonal V-shape pits with pits densities of approximately 107 and 108 cm-2, whereas, the SI GaN substrates exhibited much larger macro-scale pits with areal densities of about 102 cm-2. X-ray diffraction results were deconvoluted in order to characterize the screw and mixed (edge and screw) dislocation densities for the studied substrates. The UID substrates exhibited screw dislocation densities of 107 and 108 cm-2 and mixed dislocation densities of 109 and 1010 cm-2. The SI substrates, however, exhibit generally lower densities of dislocations of 109 and 108 cm-2 for screw and mixed, respectively. Cathodoluminescence measurements demonstrated interesting results for the UID and SI substrates with energies of 4 and 3.5 eV, respectively. The transmission measurements for the UID substrates showed that the bandgap energy was 3.39 eV.
Author: Zhe Chuan Feng
Publisher: Imperial College Press
ISBN: 1860949037
Category : Technology & Engineering
Languages : en
Pages : 442
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Book Description
III-Nitride semiconductor materials OCo (Al, In, Ga)N OCo are excellent wide band gap semiconductors very suitable for modern electronic and optoelectronic applications. Remarkable breakthroughs have been achieved recently, and current knowledge and data published have to be modified and upgraded. This book presents the new developments and achievements in the field. Written by renowned experts, the review chapters in this book cover the most important topics and achievements in recent years, discuss progress made by different groups, and suggest future directions. Each chapter also describes the basis of theory or experiment. The III-Nitride-based industry is building up and new economic developments from these materials are promising. It is expected that III-Nitride-based LEDs may replace traditional light bulbs to realize a revolution in lighting. This book is a valuable source of information for engineers, scientists and students working towards such goals. Sample Chapter(s). Chapter 1: Hydride Vapor Phase Epitaxy of Group III Nitride Materials (540 KB). Contents: Hydride Vapor Phase Epitaxy of Group III Nitride Materials (V Dmitriev & A Usikov); Planar MOVPE Technology for Epitaxy of III-Nitride Materials (M Dauelsberg et al.); Close-Coupled Showerhead MOCVD Technology for the Epitaxy of GaN and Related Materials (E J Thrush & A R Boyd); Molecular Beam Epitaxy for III-N Materials (H Tang & J Webb); Growth and Properties of Nonpolar GaN Films and Heterostructures (Y J Sun & O Brandt); Indium-Nitride Growth by High-Pressure CVD: Real-Time and Ex-Situ Characterization (N Dietz); A New Look on InN (L-W Tu et al.); Growth and Optical/Electrical Properties of Al x Ga 1-x N Alloys in the Full Composition Range (F Yun); Optical Investigation of InGaN/GaN Quantum Well Structures Grown by MOCVD (T Wang); Clustering Nanostructures and Optical Characteristics in InGaN/GaN Quantum-Well Structures with Silicon Doping (Y-C Cheng et al.); III-Nitrides Micro- and Nano-Structures (H M Ng & A Chowdhury); New Developments in Dilute Nitride Semiconductor Research (W Shan et al.). Readership: Scientists; material growers and evaluators; device design, processing engineers; postgraduate and graduate students in electrical & electronic engineering and materials engineering.
Author: Eunjung Cho
Publisher:
ISBN: 9783832284312
Category :
Languages : en
Pages : 146
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Author: Dirk Ehrentraut
Publisher: Springer Science & Business Media
ISBN: 3642048307
Category : Science
Languages : en
Pages : 337
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Book Description
This book discusses the important technological aspects of the growth of GaN single crystals by HVPE, MOCVD, ammonothermal and flux methods for the purpose of free-standing GaN wafer production.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 185
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 6
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We report the morphological and compositional characteristics and their effect on optical properties of Er-doped GaN grown by solid source molecular beam epitaxy on sapphire and hydride vapor phase epitaxy GaN substrates. The GaN was grown by molecular beam epitaxy on sapphire substrates using solid sources (for Ga, Al, and Er) and a plasma gas source for N2. The emission spectrum of the GaN:Er films consists of two unique narrow green lines at 537 and 558 nm along with typical Er31 emission in the infrared at 1.5 micrometers. The narrow lines have been identified as Er31 transitions from the 2H(sub 11/2) and 4S(sub 3/2) levels to the 4I(sub 15/2) ground state. The morphology of the GaN:Er films showed that the growth resulted in either a columnar or more compact structure with no effect on green light emission intensity.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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The research conducted for this dissertation involved two tasks important to the achievement of (1) increased breakdown fields and improved ohmic and rectifying contacts in future III-nitride devices and (2) GaN substrates for homoepitaxial growth of III-nitride films and material device structures with low densities of defects. The initial phase of this work involved the determination of an effective technique for the removal of oxygen and hydrocarbon contamination from GaN(0001) and AlN(0001) surfaces without damage to the as-received microstructure. It was determined via the combined use of x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, low energy electron diffraction, and atomic force microscopy (AFM) that a chemical vapor treatment with ammonia in an ultrahigh vacuum environment removed this contamination from these surfaces. The optimal conditions for both n- and p-type GaN were 860 & deg;C for 15 minutes at 10−4 Torr. Complete removal of the contaminants from the AlN surface required 1120 & deg;C for 30 minutes at 10−4 Torr . The microstructures of the surfaces of each material were undamaged. Important electrical and optical properties of the treated surfaces were determined, including the band bending, the electron affinity, and the elemental core level positions. The technique was subsequently employed to clean the surface of a GaN thin film substrate previously deposited and contained within a metal-organic vapor phase epitaxy (MOVPE) reactor. The introduction of ammonia into the gas mixture during heating resulted in substantial reduction in the contamination on this substrate, as determined via depth profile secondary ion mass spectroscopy at the heteroepitaxial interface between the substrate and a subsequently grown GaN film. This cleaning procedure also improved the microstructure of the homoepitaxial layer. The rapid growth of thick GaN films was achieved via the reaction between I-containing species an.
Author: Wui Hean Goh
Publisher:
ISBN:
Category : Crystal growth
Languages : en
Pages :
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Book Description
The objective of this project is to establish a new technology to grow high quality GaN based material by nano selective area growth (NSAG). The motivation is to overcome the limit of the conventional growth method, which yield a high density of dislocation in the epitaxial layer. A low dislocation density in the epitaxial layer is crucial for high performance and high efficiency devices. This project focuses on growth and material characterization of GaN based nanostructures (nanodots and nanostripes) grown using the NSAG method that we developed. NSAG, with a precise control of diameter and position of nanostructures opens the door to new applications such as: 1) single photon source, 2) photonic crystal, 3) coalescence of high quality GaN template, and 4) novel nanodevices.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Author: Marius Grundmann
Publisher: Springer Science & Business Media
ISBN: 3642561497
Category : Science
Languages : en
Pages : 450
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Book Description
Traces the quest to use nanostructured media for novel and improved optoelectronic devices. Leading experts - among them Nobel laureate Zhores Alferov - write here about the fundamental concepts behind nano-optoelectronics, the material basis, physical phenomena, device physics and systems.
