Download or read book Selective Oxidation of Aluminum bearing III V Semiconductors with Application to Quantum Well Heterostructure Lasers written by Steven Andrew Maranowski and published by . This book was released on 1995 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selective Oxidation of Aluminum bearing III V Semiconductors written by Eugene I-Chun Chen and published by . This book was released on 1996 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the water vapor oxidation of Al-bearing III-V compound semiconductors is used to fabricate light-emitting and electronic devices. High Al-composition heterostructure crystals such as Al$sb{rm x}$Ga$sb{rm 1-x}$As (x $sbsp{sim}{>}$ 0.5) are converted into a stable native oxide at moderately elevated temperatures ($sbsp{sim}{>}400 spcirc$C) in a water vapor saturated ambient. Dependence of the oxidation process on Al composition makes possible the formation of embedded oxide layers in between semiconductor crystal using selective (lateral) oxidation. Data are presented showing how various growth parameters, crystal layering, and oxidation times and temperatures affect the lateral oxidation process. Etch studies of superlattice structures that are Zn-diffused and oxidized are also presented showing that the water vapor oxidation process behaves similarly to chemical wet etches. Native oxide-based AlGaAs-GaAs metal-oxide-semiconductor field-effect transistor devices are fabricated via lateral oxidation of a thin AlAs layer. Data are presented demonstrating depletion-mode transistor operation. This shows that the native oxide is of sufficient quality to allow modulation of an underlying GaAs channel. Impurity-induced layer disordering (IILD) and water vapor oxidation are also used to define a planar minidisk cavity in a superlattice (70 A AlAs + 30 A GaAs) crystal. Data are presented showing photopumped "whispering gallery mode" laser operation of $sim$37 $mu$m minidisks lasers. Finally, the IILD and oxidation process is extended to the formation of a microdisk photonic lattice. Data are presented showing that the microdisks ($sim$9 $mu$m diameter) are sufficiently coupled to form "bands" in the photopumped recombination radiation spectra.

Download or read book Selective Oxidation of Aluminum Bearing III V Semiconductors with Applications to Quantum Well Heterostructure Lasers written by Steven Andrew Maranowski and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present work, a water vapor oxidation process is used to convert high Al-composition $rm Alsb{x}Gasb{1-x}As and Insb{0.5}(Alsb{x}Gasb{1-x})sb{0.5}P$ to stable, device-quality native oxides. The insulating and low-refractive-index properties of the native oxide prove useful in the fabrication of quantum well heterostructure laser diodes. The rate of oxide formation is sensitive to oxidation temperature and time, crystal doping, and, most dramatically the aluminum composition of the oxidizing layer. The higher aluminum composition semiconductors oxidize more readily. Selective oxidation of quantum well heterostructure crystals is used to convert only the highest aluminum composition materials to the native oxide. In the layered heterostructures commonly used in today's optoelectronic devices, selective oxidation is a unique way to "bury" an insulating and low-refractive-index oxide both above and below semiconductor layers used in a device. This makes possible, as described here, an edge-emitting laser diode that is confined both optically and electrically by "buried" oxide layers above and below the active region. Selective oxidation of $rm Alsb{x}Gasb{1-x}As$ occurs at low enough temperatures $(400spcirc$C-500$spcirc$C) to be performed on a fully metallized laser diode without adversely affecting its electrical performance. Metallized laser diodes are oxidized from their exposed facets, resulting in edge-emitting devices with current-blocking window regions at the mirrors. The buried oxide "spike," which extends from the facet into the crystal, forms selectively in a region of high aluminum composition. The buried oxide removes the current injection from the facet region, protects the facet, and results in improved maximum output powers from the lasers. Finally, the ability to form low-index $rm(nsim1.55)$ layers of oxide between high-index semiconductor crystals facilitates the formation of high-index-contrast distributed Bragg reflecting (DBR) mirrors. The properties of these mirrors and their applications to vertical cavity surface emitting lasers and edge-emitting lasers are described.

Download or read book Selective Oxidation of Aluminum bearing III V Semiconductors Properties and Applications to Small volume Quantum Well Heterostructure Lasers written by Michael John Ries and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the water-vapor oxidation of Al-bearing III-V compound semiconductors is used to fabricate small-volume semiconductor light-emitting devices. The oxidized material, native to the crystal, is mechanically and chemically stable. In addition, it is electrically insulating and has a low refractive index making it useful for defining optical cavities and current paths. The oxidation rate is sensitive to the Al composition of the material, permitting selective oxidation of "buried" high-Al-composition layers. The selective oxidation of "buried" layers is used in this work to fabricate laser cavities that are small in volume. Small-volume cavities, called microcavities, are known to exert control over the recombination of carriers within the cavity, and may be exploited to create devices with improved laser characteristics. In this work, the embedded oxide is used to form the distributed Bragg reflecting (DBR) mirrors of a vertical-cavity surface-emitting laser (VCSEL), resulting in a very high index-contrast mirror and, consequently, a very compact VCSEL cavity that exhibits microcavity effects very strongly. Another form of microcavity, the microdisk laser, is fabricated using the oxide process. The microdisk laser (10 $mu$m in diameter) rests on the low-index, thermally conductive native oxide and exhibits laser modes characteristic of "whispering gallery" modes propagating around the perimeter of the disk. Low threshold pump intensities indicate that these microdisk lasers are high-Q cavities. By combining impurity-induced layer disordering (IILD) with the oxidation process, a planar minidisk laser is fabricated. The minidisk laser is larger in diameter (37 $mu$m) and is entirely planar. The minidisk laser operates in "whispering gallery" modes around the perimeter of the disk, indicating the feasibility of the combination of processes in fabricating disk lasers. The same IILD + oxidation process is used to fabricate a two-dimensional active photonic lattice that is comprised of $sim$9-$mu$m microdisk lasers that are arranged in a triangular (hexagonal close-packed) lattice arrangement. The disks are closely spaced (11-$mu$m center-to-center spacing) such that they are strongly coupled. As a result of the coupling of the disks, the photonic lattice exhibits laser operation in bands of energy located around the microdisk modes. In addition, the photonic lattice emits beams of energy along six symmetrical "crystal" directions. The details of photonic lattice fabrication and characterization are described.

Download or read book Selective Oxidation of Al bearing III V Semiconductors written by Michael John Ries and published by . This book was released on 1996 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Native Oxides on Aluminum bearing III V Semiconductors written by Alan Richard Sugg and published by . This book was released on 1993 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Native Oxidation of Aluminum bearing III V Semiconductors with Applications to Edge and Surface emitting Lasers and to the Stabilization of Light Emitting Diodes written by Timothy Allen Richard and published by . This book was released on 1995 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, a water vapor oxidation process is used to convert high Al composition $rm Alsb{x}Gasb{1-x}As$ to a stable native oxide. The native oxides described are formed at temperatures in the range of 400$rmspcirc C$ to 500$rmspcirc C.$ Some of the basic properties of the native oxide are described. These properties include the insulating and diffusion masking nature of the oxide as well as the anisotropic behavior of the oxidation process. The high quality native oxide is then applied to laser devices in the $rm Alsb{x}Gasb{1-x}$As-GaAs and $rm Alsb{y}Gasb{1 -y}$As-GaAs-In$rmsb{x}Gasb{1-x}As$ material systems and to the stabilization of $rm Alsb{y}Gasb{1-y}As$-$rm Insb{0.5}(Alsb{x}Gasb{1-x})sb{0.5}P$ light emitting diodes. Data are presented on a high-performance native-oxide coupled-stripe $rm Alsb{y}Gasb{1-y}As$-GaAs-In$rmsb{x}Gasb{1-x}As$ quantum well heterostructure laser array realized by the "wet" oxidation of the upper $rm Alsb{y}Gasb{1-y}As$ confining layer for current definition. Also, data are presented on the (300 K and 77 K) continuous photopumped laser operation of oxide-embedded $rm Alsb{y}Gasb{1-y}As$-GaAs-In$rmsb{x}Gasb{1-x}As$ quantum-well heterostructures. The active region is sandwiched within native-oxide-semiconductor stacks. The native-oxide layers are formed after crystal growth by selectively oxidizing along high Al-composition heterolayers. The active region is shown to remain intact without any significant degradation in laser performance. The oxide-embedded laser structure is optimized for vertical-cavity laser operation utilizing large-index-step high-contrast distributed Bragg reflector mirrors formed by the selective lateral oxidation process. Edge- and vertical-cavity photopumped operations of devices with short period upper and lower mirrors are demonstrated. The vertical-cavity lasers also exhibit "hot"-carrier recombination. Finally, data are presented on the electrical behavior and the reliabillty of post-fabrication native-oxide-passivated visible-spectrum AlGaAs-In(AlGa)P p-n heterostructure light emitting diodes (LEDs). The LEDs are oxidized after metallization, thus sealing all of the exposed AlGaAs crystal at cracks, fissures, and edges against atmospheric hydrolysis without degrading their light-output characteristics. The current-voltage (I-V) characteristics of the oxide-passivated LEDs are shown to exhibit normal p-n diode behavior. Above all, the reliability of the oxidized devices in high-humidity conditions is greatly improved compared to those of otherwise identical unoxidized LEDs.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1996 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1997 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Native Oxides on Aluminum Bearing Iii V Semiconductors With Applications to High Performance Laser Diodes written by and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Native Oxides on Aluminum bearing III V Semiconductors with Applications to High Performance Laser Diodes written by Frederick Anthony Kish and published by . This book was released on 1992 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Aluminum Bearing III V Semiconductor Native Oxides for Optical and Current Confinement in Waveguides and Lasers written by Stephen Joseph Caracci and published by . This book was released on 1993 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data are presented on various laser and optical devices that utilize native oxidation of Al bearing III-V semiconductors to effect large lateral index steps. These large index steps are due to the low refractive index of the Al bearing native oxide (n $sim$ 1.5), making possible the fabrication of high-quality optical waveguides. To process epitaxial III-V crystals at higher resolution (e.g., laser devices with small output apertures and lower threshold currents), it is often desirable to shrink the thickness of the upper confining layer (UCL). The effect of thin upper confining layers on laser performance is studied by reducing the thickness to 0.2, 0.3, 0.45, and 0.6 $mu$m. Data presented show that device performance is not significantly degraded until the UCL thickness is reduced $sim$0.2 $mu$m. Planar native-oxide index-guided lasers with high-performance operation are described. These lasers use a relatively thick native oxide to form a lateral waveguide with an effective index step of $rmDelta n sim 5times10sp{-3}.$ Index-guided devices, as opposed to gain-guided devices, exhibit improved output beam quality, lower threshold current, and narrower spectra. With even larger lateral index steps it is possible to "steer" photons. To investigate very large index steps formed from native oxides, three types of devices are used: planar native-oxide defined waveguides, "teardrop"-shaped lasers and ring lasers. Data presented on native-oxide defined S-bend waveguides indicate extremely low optical losses are achieved even for "tight" bending. Further data on half- and full-ring lasers demonstrate that the radiation losses due to bending are low enough to still have high output power and low threshold current laser operation. It is even possible to select the polarization of the emitted light due to asymmetric losses for TE and TM light. This is accomplished by using a "teardrop"-shaped resonator consisting of a single output stub which is split into a y-section that is then closed with a half ring. Laser devices using this geometry exhibit TM polarized output light with low threshold currents and high output powers.

Download or read book Native Oxides on Aluminum bearing III V Semiconductors with Applications to Single mode Behavior Bistability and Switching written by Nada Abdullatif El-Zein and published by . This book was released on 1995 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, water vapor oxidation of Al-bearing III--V semiconductors is employed to form high quality native oxides. The native oxides described are formed at temperatures in the range of 400$spcirc$C to 450$spcirc$C. Some of the basic properties of the oxide are first described. The properties include the insulating and diffusion masking nature of the oxide as well as its low index of refraction. Device-quality insulating oxides are demonstrated in the $rm Alsb{x}Gasb{1-x}$As-GaAs and $rm Alsb{y}Gasb{1-y}$As-GaAs-$rm Insb{x}Gasb{1-x}As$ systems and are employed for current confinement in stripe-geometry gain guided laser diodes. The insulating properties and low refractive index (n $sim$ 1.6) of AlGaAs native oxide are employed to fabricate single-longitudinal-mode planar native-oxide AlGaAs-GaAs quantum well heterostructure (QWH) laser diodes. This is done by patterning the stripes into a linear array. Data are also presented on the use of the native oxide to obtain switching and bistability with large hysteresis when fabricating laser diodes. Three-terminal bistable devices are examined. Finally, data are presented on the wavelength selectivity of the native oxide bistable devices.

Download or read book Laser Ablation in Liquids written by Guowei Yang and published by CRC Press. This book was released on 2012-02-22 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the fundamental concepts and physical and chemical aspects of pulsed laser ablation of solid targets in liquid environments and its applications in the preparation of nanomaterials and fabrication of nanostructures. The areas of focus include basic thermodynamic and kinetic processes of laser ablation in liquids, and its applic

Download or read book Compound Semiconductor Photonics written by Chua Soo-Jin and published by CRC Press. This book was released on 2020-03-26 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceeding is a collection of selected papers presented at Symposium O of Compound Semiconductor Photonics in the International Conference on Materials for Advanced Technology (ICMAT), which was held in Singapore from 28 June to 3 July 2009. The symposium covers a wide range of topics from fundamental semiconductor materials study to photonic device fabrication and application. The papers collected are of recent progress in the active and wide range of semiconductor photonics research. They include materials-related papers on III-As/P, III-nitride, quantum dot/wire/dash growth, ZnO, and chalcogenide, and devices-related papers on photonic crystals, VCSEL, quantum dot/dash lasers, LEDs, waveguides, solar cells and heterogeneous integrat

Download or read book Sensing and Monitoring Technologies for Mines and Hazardous Areas written by Swadesh Chaulya and published by Elsevier. This book was released on 2016-06-10 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensing and Monitoring Technologies for Mines and Hazardous Areas: Monitoring and Prediction Technologies presents the fundamentals of mining related geotechnical risk and how the latest advances in sensing and data communication can be used both to prevent accidents and provide early warnings. Opencast mining operations involve huge quantities of overburden removal, dumping, and backfilling in excavated areas. Substantial increases in the rate of accumulation of waste dumps in recent years has resulted in greater height of dumps and also has given rise to the danger of dump failures as steeper open pit slopes are prone to failure. These failures lead to loss of valuable human lives and damage to mining machinery. This book presents the most recent advances in gas sensors, methane detectors, and power cut-off systems. It also introduces monitoring of the gas strata and environment, and an overview of the use of Internet of Things and cloud computing for mining sensing and surveillance purposes. Targeted at geotechnical and mining engineers, this volume covers the latest findings and technology to prevent mining accidents and mitigate the inherent risk of the activity. Presents complete details of a real-time slope stability monitoring system using wireless sensor networking and prediction technique based on multivariate statistical analysis of various parameters and analytical hierarchy process methods Discusses innovative ideas and new concepts of sensing technologies, mine transport surveillance, digital mining, and cloud computing to improve safety and productivity in mining industry Includes slope stability prediction software, downloadable through a companion website, which can be used for monitoring, analyzing, and storing different sensors and providing audio-visual, SMS, and email alerts Covers the latest findings and technology to prevent mining accidents and mitigate the inherent risk

Download or read book Semiconductor Material and Device Characterization written by Dieter K. Schroder and published by John Wiley & Sons. This book was released on 2015-06-29 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Third Edition updates a landmark text with the latest findings The Third Edition of the internationally lauded Semiconductor Material and Device Characterization brings the text fully up-to-date with the latest developments in the field and includes new pedagogical tools to assist readers. Not only does the Third Edition set forth all the latest measurement techniques, but it also examines new interpretations and new applications of existing techniques. Semiconductor Material and Device Characterization remains the sole text dedicated to characterization techniques for measuring semiconductor materials and devices. Coverage includes the full range of electrical and optical characterization methods, including the more specialized chemical and physical techniques. Readers familiar with the previous two editions will discover a thoroughly revised and updated Third Edition, including: Updated and revised figures and examples reflecting the most current data and information 260 new references offering access to the latest research and discussions in specialized topics New problems and review questions at the end of each chapter to test readers' understanding of the material In addition, readers will find fully updated and revised sections in each chapter. Plus, two new chapters have been added: Charge-Based and Probe Characterization introduces charge-based measurement and Kelvin probes. This chapter also examines probe-based measurements, including scanning capacitance, scanning Kelvin force, scanning spreading resistance, and ballistic electron emission microscopy. Reliability and Failure Analysis examines failure times and distribution functions, and discusses electromigration, hot carriers, gate oxide integrity, negative bias temperature instability, stress-induced leakage current, and electrostatic discharge. Written by an internationally recognized authority in the field, Semiconductor Material and Device Characterization remains essential reading for graduate students as well as for professionals working in the field of semiconductor devices and materials. An Instructor's Manual presenting detailed solutions to all the problems in the book is available from the Wiley editorial department.