Download or read book Photoluminescence Excitation Spectroscopy of Carbon Doped Gallium Nitride written by and published by . This book was released on 1999 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have done a comparative study of carbon-doped GaN and undoped GaN utilizing photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies in order to investigate deep levels involved in yellow luminescence (YL) and red luminescence (RL). When the GaN was excited by above-bandgap light, red luminescence (RL) centered at 1.82 eV was the dominant below-gap PL from undoped GaN, but carbon-doped GaN below-gap PL was dominated by yellow luminescence (YL) centered at 2.2 eV. When exciting PL below the band- gap with 2.4 eV light, undoped GaN had a RL peak centered at 1.5 eV and carbon-doped GaN had a RL peak centered at 1.65 eV. PLE spectra of carbon-doped GaN, detecting at 1.56 eV, exhibited a strong, broad excitation band extending from about 2,1 to 2.8 eV with an unusual shape that may be due to two or more overlapping excitation bands. This RL PLE band was not observed in undoped GaN. We also demonstrate that PL spectra excited by below gap light in GaN films on sapphire substrates are readily contaminated by 1.6-1.8 eV and 2.1-2.5 eV chromium-related emission from the substrate. A complete characterization of the Cr emission and excitation bands for sapphire substrates enables the determination of the excitation and detection wavelengths required to obtain GaN PL and PLE spectra that are free of contributions from substrate emission.

Download or read book Photoluminescence from Gan Co doped with C and Si written by Mykhailo Vorobiov and published by . This book was released on 2018 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis devoted to the experimental studies of yellow and blue luminescence (YL and BL relatively) bands in Gallium Nitride samples doped with C and Si. The band BLc was at first observed in the steady-state photoluminescence spectrum under high excitation intensities and discerned from BL1 and BL2 bands appearing in the same region of the spectrum. Using the time-resolved photoluminescence spectrum, we were able to determine the shape of the BLc and its position at 2.87 eV. Internal quantum efficiency of the YL band was estimated to be 90%. The hole capture coefficient of the BLc related state was determined as 7 10−10 cm3/s. Properties of BLc were investigated. The YL and BLc bands are attributed to electron transitions via the (0/- ) and (+/0) transition levels of the Cn defect.

Download or read book Electrical Optical and Defect Properties of Carbon doped Gallium Nitride Grown by Molecular beam Epitaxy written by Robert David Armitage and published by . This book was released on 2003 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selective Excitation of the Yellow and Blue Luminescence in N and P doped Gallium Nitride written by John Snyder Colton and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Selective Excitation of the Yellow and Blue Luminescence in N and P doped Gallium Nitride written by and published by . This book was released on 2000 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN is an interesting material: technologically very useful, but still having many unexplained features. Two such features are the broad defect-related luminescence bands: the YL of n-type GaN and the BL of Mg-doped p-type GaN. We have employed selective excitation to investigate these bands. In the case of the YL, most of the previous evidence has supported a recombination model between distant donors and acceptors, most likely a transition involving a shallow donor to a deep acceptor. Our selective excitation experiments have resolved finer structures within the YL. Our results indicate that the YL in bulk samples is related to the YL in film samples. We suggest that selectively excited YL involves recombination at DAP complexes, rather than between spatially distant DAPs (however other recombination channels, including that of distant DAPs may become significant under other excitation conditions). Characteristics of the DAP complexes within our YL model include (a) an electron localization energy of around 60-70 meV, (b) a localized phonon energy of around 40 meV, and (c) excited states of the complex at 200 and 370 meV above the ground state. In the case of the BL, the deep defect responsible for the BL is unknown, and there may not even be a deep defect involved. Also in dispute is the role of potential fluctuations in the properties of the BL. Our results have been explain in a model whereby emission is from DAPs, and significant effects are produced by doping-related potential fluctuations and disorder. Characteristics of the our model for the BL include (a) an Urbach tail, having width E0 = 33 meV, (b) a strong electron-LO phonon coupling occurring with a Frank-Condon shift of (almost equal to) 180 meV between excitation and emission, (c) a mobility gap at 2.8 eV, separating highly mobile states and highly localized states, and (d) PL-like behavior for excitation energies larger than 2.8 eV, having a blue-shift with increasing excitation energy caused by the increased number of free carriers in the material.

Download or read book Photoluminescence Studies of Recombination Mechanisms in Carbon doped Gallium Arsenide written by Lorraine Calderon and published by . This book was released on 1992 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaN and Related Alloys written by and published by . This book was released on 2000 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photoluminescence Studies of Extremely Heavily Carbon Doped Gallium Arsenide written by Bradley John Aitchison and published by . This book was released on 1990 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Luminescent Semiconductor Materials written by Leah Bergman and published by CRC Press. This book was released on 2016-04-19 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to stud

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 Proceedings of the Symposium on Light Emitting Devices for Optoelectronic Applications and the Twenty Eighth State of the Art Program on Compound Semiconductors written by H. Q. Hou and published by The Electrochemical Society. This book was released on 1998 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rare Earth and Transition Metal Doping of Semiconductor Materials written by Volkmar Dierolf and published by Woodhead Publishing. This book was released on 2016-01-23 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rare Earth and Transition Metal Doping of Semiconductor Material explores traditional semiconductor devices that are based on control of the electron’s electric charge. This book looks at the semiconductor materials used for spintronics applications, in particular focusing on wide band-gap semiconductors doped with transition metals and rare earths. These materials are of particular commercial interest because their spin can be controlled at room temperature, a clear opposition to the most previous research on Gallium Arsenide, which allowed for control of spins at supercold temperatures. Part One of the book explains the theory of magnetism in semiconductors, while Part Two covers the growth of semiconductors for spintronics. Finally, Part Three looks at the characterization and properties of semiconductors for spintronics, with Part Four exploring the devices and the future direction of spintronics. Examines materials which are of commercial interest for producing smaller, faster, and more power-efficient computers and other devices Analyzes the theory behind magnetism in semiconductors and the growth of semiconductors for spintronics Details the properties of semiconductors for spintronics

Download or read book Fabrication and Characterization of Gallium Nitride Electroluminescent Devices Co doped with Rare Earth and Silicon written by Wang Rui and published by . This book was released on 2009 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rare Earth (RE) doped III-nitrides are being widely investigated for potential applications in optical communication and displays, due to the wide and direct energy bandgap of GaN resulting in low thermal quenching of RE ion sharp emission from ultraviolet (UV) through visible to infrared (IR) region. The UC Nanolab has been conducting RE doped GaN research for more than 10 years and many achievements were obtained, ranging from material growth to device fabrication. This dissertation studied RE emission in GaN material, focusing on the effects of electronic impurity (Si) co-doping on RE luminescence. Advanced RE doped GaN electroluminescent devices (ELDs) were also designed and fabricated. Detailed device characterization was carried out and the effect of co-dopant was investigated. Eu-doped GaN thin films were grown on sapphire wafers by molecular beam epitaxy (MBE) technique and the growth conditions were optimized for the strongest Eu luminescence. It was found that GaN thin film quality and Eu doping concentration mutually affected Eu luminescence. High quality GaN:Eu thin films were grown under Ga rich condition (III/V>1), but the strongest Eu luminescence was obtained under slightly N rich condition (III/V1). The optimum Eu doping concentration is ~0.1-1.0at.%, depending on the GaN:Eu thin film quality. Higher growth temperature (750°C) was also found to enhance Eu luminescence intensity (~10x) and efficiency (~30x). The effect of Si co-doping in GaN:RE thin films was investigated. Eu photoluminescence (PL) was enhanced ~5-10x by moderate Si co-doping (~0.05at.%) mostly due to the increase of Eu PL lifetime, but decreased very fast at high Si co-doping concentration (>0.08at.%). The increase of Eu PL lifetime is possibly due to the incorporation of Si uniformly distributing Eu ions and shielding Eu-Eu interactions. Combined with the increase in excitation cross section and carrier flux, there is a significant enhancement on Eu PL intensity. The electrical properties of GaN:RE thin films were changed from high resistive to weakly n-type due to increased electron concentration introduced by Si co-doping. GaN:RE ELDs were fabricated and the electrical and optical properties were studied by I-V and electroluminescence (EL) measurements. A hetero-junction PIN structure was designed on n-GaN:Si/GaN:RE/p-Si, employing p-Si substrates as p-type conductive layer. RE ions EL emission was found to be much stronger under forward bias than under reverse bias. The Si co-doping was also studied in GaN:RE ELDs. It was found that Er EL had strong visible & IR emission under forward bias, while there is little or no emission under reverse bias. A pn hetero-junction structure formed between p-Si and n-GaN:(Si, Er) layers was proposed to be responsible for the emission control. GaN:(Si, Eu) AC thin film ELDs were also fabricated and shown that the Si co-doping increased the Eu ions emission intensity and efficiency.

Download or read book Ceramic Abstracts written by and published by . This book was released on 2000 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: