196,608 research outputs found
Strain relaxation, extended defects and doping effects in InxGa1-xN/GaN heterostructures investigated by surface photovoltage
No full textsponsorship: This work was supported by the EU under Project No. PITN-GA-2008-213238 (RAINBOW). Ana Cros acknowledges financial support from project PROMETEO/2018/123 from Generalitat Valenciana and project ENE2016-79282-C5-3-R cofinanced by the Spanish MICINN and FEDER. (EU|PITN-GA-2008-213238, Generalitat Valenciana|PROMETEO/2018/123, Spanish MICINN|ENE2016-79282-C5-3-R, FEDER|ENE2016-79282-C5-3-R)status: Publishe
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
NOVEL NANO-TEMPLATE TECHNOLOGY AND ITS APPLICATIONS TO THE FABRICATION OF NOVEL PHOTONIC DEVICES
No full textElectrical characterization of 2DEG transport properties in In0.14Al0.86N/AlN/GaN heterostructures
No full textInAlN/AlN/GaN heterostructures have a high potential to be used in HEMTs because of
their ability to provide high electron mobility and high 2D electron gas density. Here we report
the characterization of MOCVD grown Al0.84In0.16N/AlN/GaN heterostructures using Four Probe
Current-Voltage (I-V) measurements. InAlN/AlN/GaN heterostructures with for different AlN
interlayer thicknesses (0-7.5nm) and also different barrier layer thicknesses have been explored.
The four probe Current-Voltage measurements have been performed at room temperature. A
change of the conduction mechanism has been observed and a model has been developed to
extract the 2DEG properties by the current-voltage characteristics. By comparing I-V and Hall
effect results we could assess the reliability of common I-V analyses in the determination of the
major transport properties of the 2DEG.. This work was supported by the EU under Project No.
PITN-GA-2008 213238_RAINBO
Defect investigation in In(Ga,Al)N-related alloy by SPM methodology
No full textNitride based alloys such as InGaN, AlInN, AlN, InN alloys and their heterostructures have attracted a lot of attention for different applications as photovoltaic solar cells, high mobility transistors (HEMT) and light emitting devices. The strong polarization fields and good free carrier confinement at the interface, the flexibility in tuning the energy gap form the basis of achieving high quality device properties in HEMTs, LEDs, LASERs, etc. The achievement of this target is hindered by the difficulty in growing high quality epitaxial layer, due to high lattice mismatch and high thermal expansion coefficients indifferences between InN and GaN or AlN. As a result, these epilayers are highly strained and are prone to relaxation by elastic or non-elastic process, leading to the formation of structural defects.
Here we will investigate the electronic and optical properties of structural defects such as threading dislocations, trenches and slip planes in indium-rich InGaN and AlInN epilayers. The electronic properties have been investigated by various Scanning probe microscopy such as Scanning Capacitance Microscopy (SCM), Kelvin Probe Force Microscopy (KPFM) and Conductive Atomic Force Microscopy (CAFM). These defects have been found to be related with leakage current paths, carrier localization and change in surface potential. The effect of these structural defects on optical properties has been investigated by Cathodo-Luminescence (CL), while their recombination strength has been studied by Electron Beam Induced Current (EBIC) measurements. The presence of a high density of threading dislocations has a detrimental effect on the emission in indium-rich InGaN. The present results on the optical and electronic properties of threading dislocations are correlated to the emission efficiency of these heterostructures investigated by photoluminescence (PL). Apart from the electronic and optical properties, their impact on the electrical devices has also been investigate
Investigation of properties of In-related alloys by AFM
No full textMOCVD grown Al1-xInxN/AlN/GaN and InxGa1-xN/GaN heterostructures have been characterized by Atomic Force Microscopy in semi-contact and conductive mode. In-related alloys consist of grain-like structures indicating step flow and 3D-growth with threading dislocations (TDs) of density equal to ~108/cm2, the origin of which is mostly attributed to lattice mismatch between GaN and sapphire. These TDs with screw or mixed components terminate at the surface of overgrown layers as V-defects, which are six-facetted inverted pyramidal structures. Strain relaxation mechanism, formation of cracks and its propagation to the surface of the samples were also investigated. With phase-imaging (in semi-contact AFM), we have traced sites of indium segregation in the V-defects, surface-relaxation and crack propagation in In-related alloys. These sites in V-defects and cracks were found to be highly conductive by current-AFM either due to the presence of In-segregation or due to lowering of potential barrier as a consequence of strain-relaxation. They may be the possible dominant cause of leakage current in Schottky diodes. Further, current-voltage characteristics were obtained using AFM tip and barrier lowering due to image charges or trapped charges at the interface could be the conduction mechanism present in these structures. This has allowed us to calculate the local 2DEG density. This work was supported by the EU under Project No. PITN-GA-2008 213238_RAINBO
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
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