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Full-Text Articles in Engineering
Motional Modes In Bulk Powder And Few-Molecule Clusters Of Tris(8-Hydroxyquinoline Aluminum) And Their Relation To Spin Dephasing, Lopamurda Das, Jennette Mateo, Saumil Bandyopadhyay, Supriyo Bandyopadhyay, Jarrod D. Edwards, John Anderson
Motional Modes In Bulk Powder And Few-Molecule Clusters Of Tris(8-Hydroxyquinoline Aluminum) And Their Relation To Spin Dephasing, Lopamurda Das, Jennette Mateo, Saumil Bandyopadhyay, Supriyo Bandyopadhyay, Jarrod D. Edwards, John Anderson
Electrical and Computer Engineering Publications
The ensemble averaged spin dephasing rate of localized electrons in the organic molecule tris(8-hydroxyquinoline aluminum) or Alq3 has been found to be significantly larger in bulk powder than in single- or few-molecule clusters confined within 1–2 nm sized nanocavities [B. Kanchibotla et al., Phys. Rev. B78, 193306 (2008)]. To understand this observation, we have compared the midinfrared absorption spectra of bulk powder and single- or few-molecule clusters. It appears that molecules have additional vibrational modes in bulk powder possibly due to multimerization. Their coupling with spin may be responsible for the increased spin dephasing rate in bulk powder.
Switching Dynamics Of A Magnetostrictive Single-Domain Nanomagnet Subjected To Stress, Kuntal Roy, Supriyo Bandyopadhyay, Jayasimha Atulasimha
Switching Dynamics Of A Magnetostrictive Single-Domain Nanomagnet Subjected To Stress, Kuntal Roy, Supriyo Bandyopadhyay, Jayasimha Atulasimha
Electrical and Computer Engineering Publications
The temporal evolution of the magnetization vector of a single-domain magnetostrictive nanomagnet, subjected to in-plane stress, is studied by solving the Landau-Lifshitz-Gilbert equation. The stress is ramped up linearly in time, and the switching delay, which is the time it takes for the magnetization to flip, is computed as a function of the ramp rate. For high levels of stress, the delay exhibits a nonmonotonic dependence on the ramp rate, indicating that there is an optimum ramp rate to achieve the shortest delay. For constant ramp rate, the delay initially decreases with increasing stress but then saturates, showing that the …
Efficacy Of Single And Double Sinx Interlayers On Defect Reduction In Gan Overlayers Grown By Organometallic Vapor-Phase Epitaxy, F. Yun, Y.-T. Moon, Y. Fu, K. Zhu, U. Ozgur, H. Morkoç, C. K. Inoki, T.S. Kuan, Ashutosh Sagar, R. M. Feenstra
Efficacy Of Single And Double Sinx Interlayers On Defect Reduction In Gan Overlayers Grown By Organometallic Vapor-Phase Epitaxy, F. Yun, Y.-T. Moon, Y. Fu, K. Zhu, U. Ozgur, H. Morkoç, C. K. Inoki, T.S. Kuan, Ashutosh Sagar, R. M. Feenstra
Electrical and Computer Engineering Publications
We report on the growth of and evolution of defects in GaN epilayers having single- and double-layer SiNx nanoporous insertion layers. The SiNx was formed in situ in the growth chamber of an organometallic vapor-phase epitaxy system by simultaneous flow of diluted silane and ammonia. The GaN epilayers and SiNx interlayers were grown on 6H-SiC substrates using three different nucleation layers, namely, low-temperature GaN, high-temperature GaN, and high-temperature AlN nucleation layers. X-ray-diffraction rocking curves and cross-sectional and plan-view transmission electron microscope analyses indicated that a nanoporous SiNx layer can reduce the dislocations density in the GaN overgrown layer to ∼3×108cm−2 …
Energy Band Bowing Parameter In Alxga1-Xn Alloys, Feng Yun, Michael A. Reshchikov, Lei He, Thomas King, Hadis Morkoç, Steve W. Novak, Luncun Wei
Energy Band Bowing Parameter In Alxga1-Xn Alloys, Feng Yun, Michael A. Reshchikov, Lei He, Thomas King, Hadis Morkoç, Steve W. Novak, Luncun Wei
Electrical and Computer Engineering Publications
Molecular-beam epitaxy grown AlxGa1−xN alloys covering the entire range of alloy compositions, 0⩽x⩽1, have been used to determine the alloy band gap dependence on its composition. The Alchemical composition was deduced from secondary ion mass spectroscopy and Rutherford backscattering. The composition was also inferred from x-ray diffraction. The band gap of the alloy was extracted from low temperature optical reflectance measurements which are relatively more accurate than photoluminescence. Fitting of the band gap data resulted in a bowing parameter of b=1.0 eV over the entire composition range. The improved accuracy of the composition and band gap determination …