Download or read book High Resolution Ultraviolet Photoluminescence Spectroscopy Study of Gallium Nitride written by William D. Herzog and published by . This book was released on 1994 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Properties Processing and Applications of Gallium Nitride and Related Semiconductors written by James H. Edgar and published by Institution of Electrical Engineers. This book was released on 1999 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on its outstanding properties, including a wide energy band gap, high thermal conductivity, and high electron drift velocity, GaN is uniquely suited for many novel devices including solar-blind UV light detectors, high power microwave transistors, and cold cathode electron emitters. This excellent reference covers the basic physical and chemical properties, surveys existing processing technology, and presents summaries of the current state-of-the-art of devices.
Download or read book Aluminum Gallium Nitride Nanostructures for High Efficiency Ultraviolet Light Sources written by Xianhe Liu and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "To date, it has remained difficult to realize efficient deep ultraviolet (UV) light emitting devices. The underlying challenges include presence of dislocations and defects, inefficient doping for Al-rich AlGaN, and poor light extraction efficiency (LEE) due to in-plane transverse magnetic polarized emission. In this thesis, we have investigated molecular beam epitaxial growth and characterization of AlGaN nanostructures, as well as applications in UV LEDs and lasers, in order to address the performance bottleneck of conventional AlGaN-based planar deep ultraviolet (UV) light emitting devices. We firstly performed a systematic study on the molecular beam epitaxial growth and charge carrier transport properties of Mg-doped AlGaN with ~60% Al composition. High hole concentration of 8.7©71017 cm-3 and mobility values between 10 and 17 cm2/(V℗ʺs) were achieved at room temperature. Under optimal condition, a resistivity of 0.7 Î♭℗ʺcm was obtained. The conduction mechanism is identified to be hole conduction in the Mg impurity band. We also studied the improvement of LEE for transverse-magnetic (TM) polarized emission by using nanowire photonic crystals. By coupling in-plane TM-polarized emission to vertical emission at [GAMMA] point, LEE can be in principle enhanced to over 90% from below 10% in the conventional planar structure. Further considering the absorption in p-AlGaN contact layer and p-metal contact grid, LEE over 30% was predicted. To demonstrate the feasibility of nanowire photonic crystal, we developed the process of selective area epitaxy (SAE) of AlGaN nanowire and further demonstrate an LED at 279 nm. Regular and uniform AlGaN nanowire arrays with precisely controlled diameter and spacing were realized in the full compositional range. An IQE of 45% at room temperature was estimated with the presence of Al-rich shell suppressing surface nonradiative recombination. Excellent electrical and optical performance were achieved, including a small turn-on voltage of 4.4 V and an output power of ~0.93 W/cm2 at a current density of 252 A/cm2. We further studied AlN nanowall LEDs, which can exhibit IQE of ~ 60% at room-temperature, a low turn-on voltage of 7 V and higher current densities > 170 A/cm2 at 12 V. We have also demonstrated electrically pumped AlGaN nanowire lasers operating at 334 nm. Due to defect-free material quality, Anderson localization of light, and Al-rich shell structure, the optical loss and absorption were minimized and the differential gain was maximized, which resulted in ultralow threshold lasing of only a few tens of A/cm2. The studies in this thesis have revealed the advantages of molecular beam epitaxy (MBE) grown AlGaN nanostructures in addressing the current challenges with deep UV optoelectronic devices. Future research on the AlGaN nanostructures is finally proposed." --
Download or read book GaN and ZnO based Materials and Devices written by Stephen Pearton and published by Springer Science & Business Media. This book was released on 2012-01-14 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AlInGaN and ZnO materials systems have proven to be one of the scientifically and technologically important areas of development over the past 15 years, with applications in UV/visible optoelectronics and in high-power/high-frequency microwave devices. The pace of advances in these areas has been remarkable and the wide band gap community relies on books like the one we are proposing to provide a review and summary of recent progress.
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoluminescence Spectroscopy of Erbium Implanted Gallium Nitride written by Myo Thaik and published by . This book was released on 1998 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Semiconductor Science and Technology written by and published by Newnes. This book was released on 2011-01-28 with total page 3572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductors are at the heart of modern living. Almost everything we do, be it work, travel, communication, or entertainment, all depend on some feature of semiconductor technology. Comprehensive Semiconductor Science and Technology, Six Volume Set captures the breadth of this important field, and presents it in a single source to the large audience who study, make, and exploit semiconductors. Previous attempts at this achievement have been abbreviated, and have omitted important topics. Written and Edited by a truly international team of experts, this work delivers an objective yet cohesive global review of the semiconductor world. The work is divided into three sections. The first section is concerned with the fundamental physics of semiconductors, showing how the electronic features and the lattice dynamics change drastically when systems vary from bulk to a low-dimensional structure and further to a nanometer size. Throughout this section there is an emphasis on the full understanding of the underlying physics. The second section deals largely with the transformation of the conceptual framework of solid state physics into devices and systems which require the growth of extremely high purity, nearly defect-free bulk and epitaxial materials. The last section is devoted to exploitation of the knowledge described in the previous sections to highlight the spectrum of devices we see all around us. Provides a comprehensive global picture of the semiconductor world Each of the work's three sections presents a complete description of one aspect of the whole Written and Edited by a truly international team of experts
Download or read book Non Equilibrium Dynamics of Semiconductors and Nanostructures written by Kong-Thon Tsen and published by CRC Press. This book was released on 2018-10-03 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of the femto-second laser has enabled us to observe phenomena at the atomic timescale. One area to reap enormous benefits from this ability is ultrafast dynamics. Collecting the works of leading experts from around the globe, Non-Equilibrium Dynamics of Semiconductors and Nanostructures surveys recent developments in a variety of areas in ultrafast dynamics. In eight authoritative chapters illustrated by more than 150 figures, this book spans a broad range of new techniques and advances. It begins with a review of spin dynamics in a high-mobility two-dimensional electron gas, followed by the generation, propagation, and nonlinear properties of high-amplitude, ultrashort strain solitons in solids. The discussion then turns to nonlinear optical properties of nanoscale artificial dielectrics, optical properties of GaN self-assembled quantum dots, and optical studies of carrier dynamics and non-equilibrium optical phonons in nitride-based semiconductors. Rounding out the presentation, the book examines ultrafast non-equilibrium electron dynamics in metal nanoparticles, monochromatic acoustic phonons in GaAs, and electromagnetically induced transparency in semiconductor quantum wells. With its pedagogical approach and practical, up-to-date coverage, Non-Equilibrium Dynamics of Semiconductors and Nanostructures allows you to easily put the material into practice, whether you are a seasoned researcher or new to the field.
Download or read book Photoconductivity and Photoluminescence Spectroscopy in Etched and Unetched Gallium Nitride GaN written by Fatima Khan and published by . This book was released on 2001 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proton Radiation and Thermal Stabilty sic of Gallium Nitride and Gallium Nitride Devices written by Kimberly K. Allums and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: In today's industry one can see a constant challenge to exceed the limits of yesterday's devices. For the last three decades, the III--V nitride semiconductors have been viewed as highly promising for semiconductor device applications. The primary focus of III--V nitrides, thus far, has been centered on light emitting diodes (LEDs), injection lasers for digital data reading and storage applications, and ultra violet photodetectors. Yet, another application is high-power electronic devices for space-borne communications systems. It is expected that GaN-based devices will be more resistant to radiation damage often encountered in space environments, though verification of this is just now being undertaken. In particular, no information is yet available about the sensitivity to radiation of devices using dielectrics such as MOSFETs. Similarly, very limited data has been reported on the effects of high-energy protons on GaN based devices of any type. For this reason the research presented in this dissertation was undertaken to study the radiation and thermal stability of gallium nitride materials and gallium nitride semiconductor diodes, with and without novel gate dielectrics such as, scandium oxide (Sc2O3) and magnesium oxide (MgO) and the ternary mix of magnesium calcium oxide (MgCaO). It was found that though environmental degradation could be a problem for MgO dielectrics, the radiation exposure itself did not produce significant damage in either the Sc2O3, MgO or MgCaO dielectrics. Much of the minimal damage occurred in the GaN as shown by photoluminescence spectroscopy (PL).
Download or read book Photoluminescence and Reflectance Study of Heteroepitaxial Gallium Nitride written by Jayakannan Jayapalan and published by . This book was released on 1998 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Luminescence Study of Ion Implanted Gallium Nitride written by Eric Silkowski and published by . This book was released on 1996-11-01 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Luminescence and absorption measurements were used to demonstrate the efficacy of ion implantation for introducing various classes of dopants into GaN. A wide range of implantation and annealing studies were performed with several dopant species (Ar, Zn, C, O, Si, Be, Mg, Nd, Er). Room temperature ion implantation was performed on MOCVD- and MBE-grown GaN samples at energies between 100 and 1150 keV with doses ranging from 1 x 10(exp 13) to 1 x 10 (exp 15)/sq cm. Conventional furnace annealing in flowing NH3 or N2 gas resulted in good implantation damage recovery at an annealing temperature of 1000 deg C for 90 min. Annealing temperature was found to be the determining factor in implantation damage recovery. It was discovered that surface degradation occurred for annealing in an NH3 environment at temperatures above 1000 deg C. An optimal annealing temperature of 1000 deg C and an optimal annealing gas environment of NH3 were found for the optical activation of Zn, Mg, Er, and Nd. Several new luminescence features were observed for the various dopants. Zn- implanted GaN was found to have a strong luminescence peak in the blue at 2.86 eV. The energetic location and width of this luminescence peak was insensitive to temperature changes and excitation intensity changes. These properties suggested that an internal Zn center transition was responsible.
Download or read book A doping and photoluminescence study of gallium nitride grown by metalorganic chemical vapor deposition written by Christopher James Eiting and published by . This book was released on 1996 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technology of Gallium Nitride Crystal Growth written by Dirk Ehrentraut and published by Springer Science & Business Media. This book was released on 2010-06-14 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
