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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Efficient Implementation Of Raid-6 Encoding And Decoding On A Field Programmable Gate Array (Fpga), David Jacob
Efficient Implementation Of Raid-6 Encoding And Decoding On A Field Programmable Gate Array (Fpga), David Jacob
Theses and Dissertations
RAID-6 is a data encoding scheme used to provide single drive error detection and dual drive error correction for data redundancy on an array of disks. Here we present a thorough study of efficient implementations of RAID-6 on field programmable gate arrays (FPGAs). Since RAID-6 relies heavily on Galois Field Algebra (GFA), an efficient implementation of a GFA FPGA library is also presented. Through rigorous performance analysis, this work shows the most efficient ways to tradeoff FPGA resources and execution time when implementing GFA functions as well as RAID-6 encoding and decoding.
Gan Heterojunction Fet Device Fabrication, Characterization And Modeling, Qian Fan
Gan Heterojunction Fet Device Fabrication, Characterization And Modeling, Qian Fan
Theses and Dissertations
This dissertation is focused on the research efforts to develop the growth, processing, and modeling technologies for GaN-based Heterojunction Field Effect Transistors (HFETs). The interest in investigating GaN HFETs is motivated by the advantageous material properties of nitride semiconductor such as large band gap, large breakdown voltage, and high saturation velocity, which make it very promising for the high power and microwave applications. Although enormous progress has been made on GaN transistors in the past decades, the technologies for nitride transistors are still not mature, especially concerning the reliability and stability of the device. In order to improve the device …
Growth, Characterization And Applications Of Multifunctional Ferroelectric Thin Films, Bo Xiao
Growth, Characterization And Applications Of Multifunctional Ferroelectric Thin Films, Bo Xiao
Theses and Dissertations
Ferroelectric materials have been extensively studied theoretically and experimentally for many decades. Their ferroelectric, piezoelectric, pyroelectric, dielectric and electro-optical properties offer great promise in various applications such as non-volatile random access memory devices, non linear optics, motion and thermal sensors, and tunable microwave devices. Advanced applications for high dielectric constant insulators and nonvolatile memories in semiconductor industry have led to a meteoric rise of interest in the ferroelectrics recently. As most studied and technically important ferroelectric materials, lead zirconate titanate (PZT) and barium strontium titanate (BST) are widely investigated to understand their properties for potential device applications. Using radio frequency …
Fabrication And Device Applications Of Self Assembled Nanostructures, Bhargava Ram Kanchibotla V
Fabrication And Device Applications Of Self Assembled Nanostructures, Bhargava Ram Kanchibotla V
Theses and Dissertations
The spin dynamics of electrons in inorganic and organic semiconducting nanostructures has become an area of interest in recent years. The controlled manipulation of an electron’s spin, and in particular its phase, is the primary requirement for applications in quantum information processing. The phase decoheres in a time known as the transverse relaxation time or T2 time. We have carried out a measurement of the ensemble-averaged transverse spin relaxation time (T2*) in bulk and few molecules of the organic semiconductor tris-(8-hydroxyquinolinolato aluminum) or Alq3. The Alq3 system exhibits two characteristic T2* times: the longer of which is temperature independent and …
Optical And Electrical Properties Of Compound And Transition Metal Doped Compound Semiconductor Nanowires, Sivakumar Ramanathan
Optical And Electrical Properties Of Compound And Transition Metal Doped Compound Semiconductor Nanowires, Sivakumar Ramanathan
Theses and Dissertations
Nanotechnology is the science and engineering of creating functional materials by precise control of matter at nanometer (nm) length scale and exploring novel properties at that scale. It is vital to understand the quantum mechanical phenomena manifested at nanometer scale dimensions since that will enable us to precisely engineer quantum mechanical properties to realize novel device functionalities. This dissertation investigates optical and electronic properties of compound and transition metal doped compound semiconductor nanowires with a view to exploiting them for a wide range of applications in semiconductor electronic and optical devices. In this dissertation work, basic concepts of optical and …
Internal Quantum Efficiency Of C-Plane Ingan And M-Plane Ingan On Si And Gan, X. Ni, J. Lee, M. Wu, X. Li, Ryoko Shimada, Ü. Özgür, A. A. Baski, Hadis Morkoç, T. Paskova, G. Mulholland, K. R. Evans
Internal Quantum Efficiency Of C-Plane Ingan And M-Plane Ingan On Si And Gan, X. Ni, J. Lee, M. Wu, X. Li, Ryoko Shimada, Ü. Özgür, A. A. Baski, Hadis Morkoç, T. Paskova, G. Mulholland, K. R. Evans
Electrical and Computer Engineering Publications
We investigated internal quantum efficiency (IQE) of polar (0001) InGaN on c-sapphire, and (11¯00) nonpolar m-plane InGaN on both m-plane GaN and specially patterned Si. The IQE values were extracted from the resonant photoluminescence intensity versus the excitation power. Data indicate that at comparable generatedcarrier concentrations the efficiency of the m-plane InGaN on patterned Si is approximately a factor of 2 higher than that of the highly optimized c-plane layer. At the highest laser excitation employed (∼1.2×1018 cm−3), the IQE of m-plane InGaN double heterostructure on Si is approximately 65%. We believe that the m-plane would remain inherently advantageous, particularly …
Degradation In Inaln/Gan-Based Heterostructure Field Effect Transistors: Role Of Hot Phonons, J. H. Leach, C. Y. Zhu, M. Wu, X. Ni, X. Li, J. Xie, Ü. Özgür, Hadis Morkoç, J. Liberis, E. Šermukšnis, A. Matulionis, H. Cheng, Ç. Kurdak
Degradation In Inaln/Gan-Based Heterostructure Field Effect Transistors: Role Of Hot Phonons, J. H. Leach, C. Y. Zhu, M. Wu, X. Ni, X. Li, J. Xie, Ü. Özgür, Hadis Morkoç, J. Liberis, E. Šermukšnis, A. Matulionis, H. Cheng, Ç. Kurdak
Electrical and Computer Engineering Publications
We report on high electric field stress measurements at room temperature on InAlN/AlN/GaN heterostructure field effect transistor structures. The degradation rate as a function of the average electron density in the GaN channel (as determined by gated Hall bar measurements for the particular gate biases used), has a minimum for electron densities around 1×1013 cm−2, and tends to follow the hot phonon lifetime dependence on electron density. The observations are consistent with the buildup of hot longitudinal optical phonons and their ultrafast decay at about the same electron density in the GaN channel. In part because they have negligible group …
On Carrier Spillover In C- And M-Plane Ingan Light Emitting Diodes, J. Lee, X. Li, X. Ni, Ü. Özgür, Hadis Morkoç, T. Paskova, G. Mulholland, K. R. Evans
On Carrier Spillover In C- And M-Plane Ingan Light Emitting Diodes, J. Lee, X. Li, X. Ni, Ü. Özgür, Hadis Morkoç, T. Paskova, G. Mulholland, K. R. Evans
Electrical and Computer Engineering Publications
The internal quantum efficiency(IQE) and relative external quantum efficiency (EQE) in InGaNlight-emitting diodes(LEDs) emitting at 400 nm with and without electron blocking layers (EBLs) on c-plane GaN and m-plane GaN were investigated in order to shed some light on any effect of polarizationcharge induced field on efficiency killer carrier spillover. Without an EBL the EQE values suffered considerably (by 80%) for both orientations, which is clearly attributable to carrier spillover. Substantial carrier spillover in both polarities, therefore, suggests that the polarizationcharge is not the major factor in efficiency degradation observed, particularly at high injection levels. Furthermore, the m-plane variety with …
Epitaxial Growth Of (001)-Oriented Ba0.5sr0.5tio3 Thin Films On A-Plane Sapphire With An Mgo/Zno Bridge Layer, Bo Xiao, Hongrui Liu, Vitaliy Avrutin, Jacob H. Leach, Emmanuel Rowe, Huiyong Liu, Ü. Özgür, Hadis Morkoç, W. Chang, L.M. B. Allredge, S. W. Kirchoefer, J. M. Pond
Epitaxial Growth Of (001)-Oriented Ba0.5sr0.5tio3 Thin Films On A-Plane Sapphire With An Mgo/Zno Bridge Layer, Bo Xiao, Hongrui Liu, Vitaliy Avrutin, Jacob H. Leach, Emmanuel Rowe, Huiyong Liu, Ü. Özgür, Hadis Morkoç, W. Chang, L.M. B. Allredge, S. W. Kirchoefer, J. M. Pond
Electrical and Computer Engineering Publications
High quality (001)-oriented Ba0.5Sr0.5TiO3 (BST) thin films have been grown on a-plane sapphire(112¯0) by rf magnetron sputtering using a double bridge layer consisting of (0001)-oriented ZnO (50 nm) and (001)-oriented MgO (10 nm) prepared by plasma-assisted molecular beam epitaxy. X-ray diffraction revealed the formation of three sets of in-plane BST domains, offset from one another by 30°, which is consistent with the in-plane symmetry of the MgO layer observed by in situ reflective high electron energy diffraction. The in-plane epitaxial relationship of BST, MgO, and ZnO has been determined to be BST [110]//MgO [110]//ZnO [112¯0] and BST [110]/MgO [110]//ZnO [11¯00]. …
Plasmon-Enhanced Heat Dissipation In Gan-Based Two-Dimensional Channels, A. Matulionis, J. Liberis, I. Matulioniene, M. Ramonas, E. Šermukšnis, J. H. Leach, M. Wu, X. Ni, X. Li, Hadis Morkoç
Plasmon-Enhanced Heat Dissipation In Gan-Based Two-Dimensional Channels, A. Matulionis, J. Liberis, I. Matulioniene, M. Ramonas, E. Šermukšnis, J. H. Leach, M. Wu, X. Ni, X. Li, Hadis Morkoç
Electrical and Computer Engineering Publications
Decay of nonequilibrium longitudinal optical (LO) phonons is investigated at room temperature in two-dimensional electron gas channels confined in nearly lattice-matched InAlN/AlN/GaN structures. A nonmonotonous dependence of the LO-phonon lifetime on the supplied electric power is reported for the first time and explained in terms of plasmon–LO-phonon resonance tuned by applied bias at a fixed sheet density (8×1012 cm−2). The shortest lifetime of 30±15 fs is found at the power of 20±10 nW/electron.
Nonpolar M-Plane Gan On Patterned Si(112) Substrates By Metalorganic Chemical Vapor Deposition, X. Ni, M. Wu, J. Lee, X. Li, A. A. Baski, Ü. Özgür, Hadis Morkoç
Nonpolar M-Plane Gan On Patterned Si(112) Substrates By Metalorganic Chemical Vapor Deposition, X. Ni, M. Wu, J. Lee, X. Li, A. A. Baski, Ü. Özgür, Hadis Morkoç
Electrical and Computer Engineering Publications
The concept of nonpolar (11¯00) m-plane GaN on Si substrates has been demonstrated by initiating growth on the vertical (1¯1¯1) sidewalls of patterned Si(112) substrates using metalorganic chemical vapor deposition. The Si(112) substrates were wet-etched to expose {111} planes using stripe-patterned SiNx masks oriented along the [1¯10] direction. Only the vertical Si(1¯1¯1) sidewalls were allowed to participate in GaNgrowth by masking other Si{111} planes using SiO2, which led to m-plane GaNfilms.Growth initiating on the Si(1¯1¯1) planes normal to the surface was allowed to advance laterally and also vertically toward full coalescence. InGaN double heterostructure active layers grown on these m-GaN …
Nanoelectrospray Aerosols From Microporous Polymer Wick Sources, Gary C. Tepper, Royal Kessick
Nanoelectrospray Aerosols From Microporous Polymer Wick Sources, Gary C. Tepper, Royal Kessick
Electrical and Computer Engineering Publications
Nanoelectrospray aerosols were formed from microporous polymer wick sources. Current-voltage characteristics were measured as a function of solution electrical conductivity and surface tension and two distinct electrospray modes were observed. In the first mode, when the maximum capillary flow rate through the wick exceeds the electrospray flow rate, a single electrospray forms from a droplet at the end of the wick. In the second mode, when the maximum capillary flow rate is less than the electrospray flow rate, a multitude of microscopic nanoelectrospray sources are formed from within the surface of the wick tip.
Retraction: “Observation Of Numerous E2 Mode Phonon Replicas In The Room Temperature Photoluminescence Spectra Of Zno Nanowires: Evidence Of Strong Deformation Potential Electron-Phonon Coupling” [Appl. Phys. Lett.89, 143121 (2006)], S. Ramanathan, Supriyo Bandyopadhyay, L. K. Hussey, M. Muñoz
Retraction: “Observation Of Numerous E2 Mode Phonon Replicas In The Room Temperature Photoluminescence Spectra Of Zno Nanowires: Evidence Of Strong Deformation Potential Electron-Phonon Coupling” [Appl. Phys. Lett.89, 143121 (2006)], S. Ramanathan, Supriyo Bandyopadhyay, L. K. Hussey, M. Muñoz
Electrical and Computer Engineering Publications
No abstract provided.
Effect Of Large Strain On Dielectric And Ferroelectric Properties Of Ba0.5sr0.5tio3 Thin Films, Bo Xiao, Vitaliy Avrutin, Hongrui Liu, Emmanuel Rowe, Jacob H. Leach, Xing Gu, Ü. Özgür, Hadis Morkoç, W. Chang, L. M.B. Alldredge, S. W. Kirchoefer, J. M. Pond
Effect Of Large Strain On Dielectric And Ferroelectric Properties Of Ba0.5sr0.5tio3 Thin Films, Bo Xiao, Vitaliy Avrutin, Hongrui Liu, Emmanuel Rowe, Jacob H. Leach, Xing Gu, Ü. Özgür, Hadis Morkoç, W. Chang, L. M.B. Alldredge, S. W. Kirchoefer, J. M. Pond
Electrical and Computer Engineering Publications
BaxSr1−xTiO3 is ideally suited as a tunable medium for radio frequency passive component. In this context we have studied the effect of biaxial strain on the dielectric and ferroelectricproperties of Ba0.5Sr0.5TiO3thin filmsgrown epitaxially on SrTiO3 (001) substrates. The lattice parameters of the films determined by high-resolution x-ray diffraction with the thickness varying from 160 to 1000 nm indicated large biaxial compressive strain which decreased from 2.54% to 1.14% with increasing film thickness. Temperature-dependent measurements of the dielectric constant in our strained Ba0.5Sr0.5TiO3thin films revealed a significant increase in the Curie temperature as the film thickness is below 500 nm. Enhanced …
Energy Relaxation Probed By Weak Antilocalization Measurements In Gan Heterostructures, H. Cheng, N. Biyikli, J. Xie, Ç. Kurdak, H. Morkoç
Energy Relaxation Probed By Weak Antilocalization Measurements In Gan Heterostructures, H. Cheng, N. Biyikli, J. Xie, Ç. Kurdak, H. Morkoç
Electrical and Computer Engineering Publications
Energy relaxation and electron-phonon (e-p) interaction are investigated in wurtzite Al0.15Ga0.85N/AlN/GaN and Al0.83In0.17N/AlN/GaN heterostructures with polarization induced two-dimensional electron gases in the Bloch–Grüneisen regime. Weak antilocalization (WAL) and Shubnikov–de Haas measurements were performed on gated Hall bar structures at temperatures down to 0.3 K. We used WAL as a thermometer to measure the electron temperature Te as a function of the dc bias current. We found that the power dissipated per electron, Pe, was proportional to T4e due to piezoelectric acoustic phonon emission by hot electrons. We calculated Pe as a function of Te without any adjustable parameters for both …
Correlated Growth Of Organic Material Tris (8-Hydroxyquinoline) Aluminum (Alq3) And Its Relation To Optical Properties, Bhargava R. Kanchibotla, K. Garre, Deeder Aurongzeb
Correlated Growth Of Organic Material Tris (8-Hydroxyquinoline) Aluminum (Alq3) And Its Relation To Optical Properties, Bhargava R. Kanchibotla, K. Garre, Deeder Aurongzeb
Electrical and Computer Engineering Publications
We report slow correlated growth mode in energetic cluster vapor deposited organic light emissive material tris(8-hydroxyquinoline) aluminum from 5 to 100 nm. Phase modulated atomic force microscopy shows very slow grain growth with thickness, with very small phase differences within the film.Fractal dimension calculated from correlation function shows growth process above 10 nm consistent with diffusion-limited aggregation. For low thickness (5 nm), photoluminescence measurement shows the emission peak is shifted by ∼0.4 eV toward lower wavelength.
Electron Drift Velocity In Lattice-Matched Alinn/Aln/Gan Channel At High Electric Fields, L. Ardaravičius, M. Ramonas, J. Liberis, O. Kiprijanovič, A. Matulionis, J. Xie, M. Wu, J. H. Leach, H. Morkoç
Electron Drift Velocity In Lattice-Matched Alinn/Aln/Gan Channel At High Electric Fields, L. Ardaravičius, M. Ramonas, J. Liberis, O. Kiprijanovič, A. Matulionis, J. Xie, M. Wu, J. H. Leach, H. Morkoç
Electrical and Computer Engineering Publications
Hot-electron transport was probed by nanosecond-pulsed measurements for a nominally undoped two-dimensional channel confined in a nearly lattice-matched Al0.82In0.18N/AlN/GaN structure at room temperature. The electric field was applied parallel to the interface, the pulsed technique enabled minimization of Joule heating. No current saturation was reached at fields up to 180 kV/cm. The effect of the channel length on the current is considered. The electron drift velocity is deduced under the assumption of uniform electric field and field-independent electron density. The highest estimated drift velocity reaches ∼3.2×107 cm/s when the AlN spacer thickness is 1 nm. At high fields, a weak …