Download or read book Study of the Photoluminescence Spectra of Mg doped GaN written by Puranjan Ghimire and published by . This book was released on 2017 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied luminescence properties of Mg-doped GaN grown by hydride vapor phase epitaxy. Steady state photoluminescence (PL) spectra have been analyzed. Exciton, ultraviolet luminescence (UVL) and blue luminescence (BL) bands are the dominant PL bands in the spectra. At low temperature, Exciton and UVL bands show almost no shift with excitation intensity, whereas the BL band blueshifts by almost 0.4 eV with increasing excitation intensity by seven orders of magnitude. Such shifting nature of bands with excitation intensity is explained by assuming that the BL band is detected from the region of the sample where potential fluctuations are very large, but the UVL and exciton bands originate from the region of the sample where there are no potential fluctuations. After the careful analysis of potential fluctuations model and the donor-acceptor pair model, we conclude that the BL band in the studied GaN:Mg sample is not a separate band but the UVL band itself, which is significantly distorted by potential fluctuations. Now, we call this band the BL* band. Temperature dependence of the BL*, UVL and Exciton peak intensity is analyzed. We see abrupt and tunable thermal quenching of the BL* and Exciton bands. Temperature dependence of the BL* and UVL bands at fixed excitation intensities but at different environmental conditions is also investigated. Finally, giant redshift of the BL* band with increasing temperature is explained by a combination of potential fluctuations and abrupt quenching of the BL* band with temperature.
Download or read book Compound Semiconductors 1996 Proceedings of the Twenty Third INT Symposium on Compound Semiconductors held in St Petersburg Russia 23 27 September 1996 written by M.S. Shur and published by CRC Press. This book was released on 2020-10-29 with total page 1096 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a comprehensive overview of developments to both the academic and industrial communities, Compound Semiconductors 1996 covers all types of compound semiconducting materials and devices. The book includes results on blue and green lasers, heterostructure devices, nanoelectronics, and novel wide band gap semiconductors. With invited review papers and research results in current topics of interest, this volume is part of a well-known series of conferences for the dissemination of research results in the field.
Download or read book JJAP written by and published by . This book was released on 2006 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time resolved Photoluminescence Studies of Point Defects in GaN written by Joy Dorene McNamara and published by . This book was released on 2016 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-resolved photoluminescence (TRPL) measurements paired with steady-state photoluminescence (SSPL) measurements can help to determine the PL lifetime, shape and position of unresolved bands, capture coefficients, and concentrations of free electrons and defects. PL bands that are obscured in the SSPL spectra can be accurately revealed by TRPL measurements. TRPL measurements are able to show if the PL band originates from an internal transition between different states of the same defect. The main defect-related PL bands in high-purity GaN grown by hydride vapor phase epitaxy (HVPE) which have been investigated are the ultraviolet, blue, green, yellow and red luminescence bands (UVL, BL, GL, YL and RL, respectively). The concentration of free electrons can be calculated from these measurements providing a contactless alternative to the Hall effect method. The lifetime of most defect-related PL bands decreases with increasing temperature. However, the lifetime of the GL band, with a maximum at 2.4 eV observed in the SSPL spectra only at high excitation intensity, increases as a function of temperature. By analyzing the PL intensity decay, the origin of the GL can be attributed to an internal transition from an excited state of the CN defect, which behaves as an optically generated giant trap, to the 0/+ level of the same defect. This first observation of an optically generated giant trap was detected by analyzing the cubic temperature dependence of the electron capture coefficient. Excitation intensity and temperature dependent studies on Mg-doped GaN grown by HVPE were performed. The position of the UVL (3.2 eV) peak blue-shifts with increasing excitation intensity, which can be explained by the presence of potential fluctuations. The BL peak (2.8 eV) also blue-shifts with increasing excitation intensity, and red-shifts as a function of temperature. These shifts can be explained by the transitions originating from a deep-donor to the MgGa acceptor, and the corresponding donor-acceptor pair nature.
Download or read book Handbook of GaN Semiconductor Materials and Devices written by Wengang (Wayne) Bi and published by CRC Press. This book was released on 2017-10-20 with total page 709 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses material growth, device fabrication, device application, and commercialization of energy-efficient white light-emitting diodes (LEDs), laser diodes, and power electronics devices. It begins with an overview on basics of semiconductor materials, physics, growth and characterization techniques, followed by detailed discussion of advantages, drawbacks, design issues, processing, applications, and key challenges for state of the art GaN-based devices. It includes state of the art material synthesis techniques with an overview on growth technologies for emerging bulk or free standing GaN and AlN substrates and their applications in electronics, detection, sensing, optoelectronics and photonics. Wengang (Wayne) Bi is Distinguished Chair Professor and Associate Dean in the College of Information and Electrical Engineering at Hebei University of Technology in Tianjin, China. Hao-chung (Henry) Kuo is Distinguished Professor and Associate Director of the Photonics Center at National Chiao-Tung University, Hsin-Tsu, Taiwan, China. Pei-Cheng Ku is an associate professor in the Department of Electrical Engineering & Computer Science at the University of Michigan, Ann Arbor, USA. Bo Shen is the Cheung Kong Professor at Peking University in China.
Download or read book JJAP Letters written by and published by . This book was released on 2002 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Progress in the Study of Point Defects written by Masao Dōyama and published by . This book was released on 1977 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book III Nitride Semiconductors written by Hongxing Jiang and published by CRC Press. This book was released on 2002-06-28 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of a comprehensive overview of fundamental optical properties of III-nitride semiconductors. All optoelectronic applications based on III-nitrides are due to their unique optical properties and characterizations of III-nitrides. Much information, which is critical to the design and improvement of optoelectronic devices based on III-nitrides has been obtained in the last several years. This is the first of a two part Volume in the series Optoelectronic Properties of Semiconductors and Superlattices. Part I begins with time-resolved studies of semiconductors and moves on to the emphasis on time-resolved photoluminescence of nitride materials and device technology and focuses on Raman studies and properties of III Nitrides. This unique volume provides a comprehensive review and introduction of the defects and structural properties of GaN and related compounds. This would be excellent for newcomers to the field and is a stimulus to further advances for experienced researchers.III-Nitride Semiconductors: Optical Properties Part I combines contributions from active experts in the field with diverse backgrounds. This book provides a very important step in advancing the state of research and device development in the field of III-nitride materials.
Download or read book Molecular Beam Epitaxy written by Mohamed Henini and published by Newnes. This book was released on 2012-12-31 with total page 745 pages. Available in PDF, EPUB and Kindle. Book excerpt: This multi-contributor handbook discusses Molecular Beam Epitaxy (MBE), an epitaxial deposition technique which involves laying down layers of materials with atomic thicknesses on to substrates. It summarizes MBE research and application in epitaxial growth with close discussion and a ‘how to’ on processing molecular or atomic beams that occur on a surface of a heated crystalline substrate in a vacuum.MBE has expanded in importance over the past thirty years (in terms of unique authors, papers and conferences) from a pure research domain into commercial applications (prototype device structures and more at the advanced research stage). MBE is important because it enables new device phenomena and facilitates the production of multiple layered structures with extremely fine dimensional and compositional control. The techniques can be deployed wherever precise thin-film devices with enhanced and unique properties for computing, optics or photonics are required. This book covers the advances made by MBE both in research and mass production of electronic and optoelectronic devices. It includes new semiconductor materials, new device structures which are commercially available, and many more which are at the advanced research stage. Condenses fundamental science of MBE into a modern reference, speeding up literature review Discusses new materials, novel applications and new device structures, grounding current commercial applications with modern understanding in industry and research Coverage of MBE as mass production epitaxial technology enhances processing efficiency and throughput for semiconductor industry and nanostructured semiconductor materials research community
Download or read book Semiconductor based Sensors written by Fan Ren and published by World Scientific. This book was released on 2016-08-26 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive summary of the status of emerging sensor technologies and provides a framework for future advances in the field. Chemical sensors have gained in importance in the past decade for applications that include homeland security, medical and environmental monitoring and also food safety. A desirable goal is the ability to simultaneously analyze a wide variety of environmental and biological gases and liquids in the field and to be able to selectively detect a target analyte with high specificity and sensitivity. The goal is to realize real-time, portable and inexpensive chemical and biological sensors and to use these as monitors for handheld gas, environmental pollutant, exhaled breath, saliva, urine, or blood, with wireless capability.In the medical area, frequent screening can catch the early development of diseases, reduce the suffering of patients due to late diagnoses, and lower the medical cost. For example, a 96% survival rate has been predicted in breast cancer patients if the frequency of screening is every three months. This frequency cannot be achieved with current methods of mammography due to high cost to the patient and invasiveness (radiation). In the area of detection of medical biomarkers, many different methods, including enzyme-linked immunsorbent assay (ELISA), particle-based flow cytometric assays, electrochemical measurements based on impedance and capacitance, electrical measurement of microcantilever resonant frequency change, and conductance measurement of semiconductor nanostructures, gas chromatography (GC), ion chromatography, high density peptide arrays, laser scanning quantitiative analysis, chemiluminescence, selected ion flow tube (SIFT), nanomechanical cantilevers, bead-based suspension microarrays, magnetic biosensors and mass spectrometry (MS) have been employed. Depending on the sample condition, these methods may show variable results in terms of sensitivity for some applications and may not meet the requirements for a handheld biosensor.
Download or read book GaN and Related Alloys Volume 537 written by S. J. Pearton and published by . This book was released on 1999-09-14 with total page 1056 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the full spectrum of activity in the GaN and related materials arena. These semiconductors are finding applications in full-color displays, high-density information storage, white lighting for outdoor or backlit displays, solar-blind UV detectors, high-power/high-temperature electronics, and covert undersea communications. Progress is been reported in the growth of thick layers on patterned substrates by various methods, leading to lower overall defect concentrations and improved current-voltage and reliability characteristics. The rapidly increasing market for blue/green LEDs is also noted by the entry of a number of new companies to the field. While these emitter technologies continue to be dominated by MOCVD material, there are exciting reports of UV detectors and HFET structures grown by MBE with device performance at least as good as by MOCVD. Topics include: GaN electronic and photonic devices; laser diodes and spectroscopy; electronic devices and processing; quantum dots and processing; novel growth, doping and processing and rare-earth doping and optical emission.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hole Transport and Photoluminescence in Mg doped InN written by and published by . This book was released on 2010 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hole conductivity and photoluminescence were studied in Mg-doped InN films grown by molecular beam epitaxy. Because surface electron accumulation interferes with carrier type determination by electrical measurements, the nature of the majority carriers in the bulk of the films was determined using thermopower measurements. Mg concentrations in a"window" from ca. 3 x 1017 to 1 x 1019 cm-3 produce hole-conducting, p-type films as evidenced by a positive Seebeck coecient. This conclusion is supported by electrolyte-based capacitance voltage measurements and by changes in the overall mobility observed by Hall effect, both of which are consistent with a change from surface accumulation on an n-type film to surface inversion on a p-type film. The observed Seebeck coefficients are understood in terms of a parallel conduction model with contributions from surface and bulk regions. In partially compensated films with Mg concentrations below the window region, two peaks are observed in photoluminescence at 672 meV and at 603 meV. They are attributed to band-to-band and band-to-acceptor transitions, respectively, and an acceptor binding energy of ~;;70 meV is deduced. In hole-conducting films with Mg concentrations in the window region, no photoluminescence is observed; this is attributed to electron trapping by deep states which are empty for Fermi levels close to the valence band edge.
Download or read book GaN and Related Alloys written by and published by . This book was released on 2004 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book GaN and Related Alloys 2003 Volume 798 written by Hock Min Ng and published by . This book was released on 2004-04-09 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.
Download or read book Handbook of Advanced Electronic and Photonic Materials and Devices Semiconductors written by Hari Singh Nalwa and published by . This book was released on 2001 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electronic and photonic materials discussed in this handbook are the key elements of continued scientific and technological advances in the 21st century. The electronic and photonic materials comprising this handbook include semiconductors, superconductors, ferroelectrics, liquid crystals, conducting polymers, organic and superconductors, conductors, nonlinear optical and optoelectronic materials, electrochromic materials, laser materials, photoconductors, photovoltaic and electroluminescent materials, dielectric materials, nanostructured materials, supramolecular and self-asemblies, silicon and glasses, photosynthetic and respiratory proteins, etc, etc. Some of these materials have already been used and will be the most important components of the semiconductor and photonic industries, computers, internet, information processing and storage, telecommunications, satellite communications, integrated circuits, photocopiers, solar cells, batteries, light-emitting diodes, liquid crystal displays, magneto-optic memories, audio and video systems, recordable compact discs, video cameras, X-ray technology, color imaging, printing, flat-panel displays, optical waveguides, cable televisions, computer chips, molecular-sized transistors and switches, as well as other emerging cutting edge technologies. Electronic and photonic materials are expected to grow to a trillion-dollar industry in the new millennium and will be the most dominating forces in the emerging new technologies in the fields of science and engineering. This handbook is a unique source of the in-depth knowledge of synthesis, processing, fabrication, spectroscopy, physical properties and applications of electronic and photonic materials covering everything for today's and developing future technologies. This handbook consists of over one hundred state-of-the-art review chapters written by more than 200 world leading experts from 25 different countries. With more than 23,000 bibliographic citations and several thousands of figures, tables, photographs, chemical structures and equations, this handbook is an invaluable major reference source for scientists and students working in the field of materials science, solid-state physics, chemistry, electrical and optical engineering, polymer science, device engineering and computational engineering, photophysics, data storage and information technology and technocrats, everyone who is involved in science and engineering of electronic and photonic materials. Key Features * This is the first handbook ever published on electronic and photonic materials * 10 volumes summarize the advances in electronic and photonic materials made over past the two decades * This handbook is a unique source of the in-depth knowledge of synthesis, processing, spectroscopy, physical properties and applications of electronic and photonic materials * Over 100 state-of-the-art review chapters written by more than 200 leading experts from 25 different countries * About 25,000 bibliographic citations and several thousand figures, tables, photographs, chemical structures and equations * Easy access to electronic and photonic materials from a single reference * Each chapter is self-contained with cross references * Single reference having all inorganic, organic and biological materials * Witten in very clear and concise fashion for easy understanding of structure property relationships in electronic and photonic materials
Download or read book III V Nitrides written by Fernando A. Ponce and published by . This book was released on 1997 with total page 1290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
