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Full-Text Articles in Engineering

Proton Irradiation Effects On Semiconductor Cdse/Zns Core/Shell Nanocrystals, Stephen Graham Charter Aug 2009

Proton Irradiation Effects On Semiconductor Cdse/Zns Core/Shell Nanocrystals, Stephen Graham Charter

Graduate Theses and Dissertations

The absorbance and photoluminescence measurement of semiconductor CdSe/ZnS core shell nanocrystals were reviewed and investigated after they were exposed to proton irradiation. The CdSe/ZnS core shell nanocrystals of 3.2nm and 4.4nm were commercially purchased and investigated. These nanocrystals were embedded in UV resin. Proton irradiation of energy 2MeV was applied at doses from 3 x 1013 protons cm-2 to 1.47 x 1015 protons cm-2 for both nanocrystal sizes. Absorbance measurements were conducted at 300K. Results from absorbance measurements showed slight broadening of the first exciton peak of both samples but was most noticeable in the 3.2nm nanocrystal sample. UV resin …


Growth And Characterization Of Chromium Doped Indium Oxide Diluted Magnetic Semiconductors, Ndubuisi Benjamin Ukah Jan 2009

Growth And Characterization Of Chromium Doped Indium Oxide Diluted Magnetic Semiconductors, Ndubuisi Benjamin Ukah

MSU Graduate Theses

Recently, enormous research efforts have been directed at diluted magnetic semiconductors (DMS) critical for realization for multi-functional spintronic devices. However, the origin of electronic and magnetic properties in DMS is not well understood. This study is aimed to better understand the structural, optical, magnetic, and magneto-transport property relationships of Cr-doped In2O3 (In2O3:Cr) DMS grown under different partial oxygen pressures on sapphire substrates using pulsed laser deposition technique. The thin films were characterized using various state-of-the-art techniques such as x-ray diffraction (XRD), UV-VIS spectroscopy, magnetotransport, and SQUID magnetometer. Expansions in lattice parameter (10.10 Å to 10.34 Å) and crystal size (13.9 …


Effect Of Mechanical Vibrations On Light Emitting Diode Luminaires, Jayalakshmi Paladugu Jan 2009

Effect Of Mechanical Vibrations On Light Emitting Diode Luminaires, Jayalakshmi Paladugu

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, a LED and two types of Compact fluorescent lamps were investigated for the intensity variation due to mechanical vibrations in the range of 0 to 30 HZ. In general, subjecting the lamps to 24-hour vibration affects the total intensity percentage variations of peak intensities after vibrations is in the range of -25 to +15% compared to those of no vibrations for the light emitting diode luminaires. For the case of compact fluorescent lamps (Nuvue) the variations are in range from +10 to +35%, whereas for the Compact fluorescent lamps (Ecosmart) the intensity peaks range from -10 to …


Individual Copper Nanowire Decorated By Gold Nanoparticles For Surface Enhanced Raman Scattering, Roshan Guttikonda Jan 2009

Individual Copper Nanowire Decorated By Gold Nanoparticles For Surface Enhanced Raman Scattering, Roshan Guttikonda

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this Thesis, I discuss the theory, implementation and applications of Surface enhanced Raman scattering (SERS). Surface enhanced Raman scattering has been used to detect 4 mercaptopyridine molecules. On a Silicon wafer, Gold nanoparticles are deposited onto Copper nanowires. Hotspots occur at the small gap (less than 10nm) between the nanowire and nanoparticle. The interaction of the electromagnetic field of the incident laser and the surface plasmon resonances of the metal nanoparticles at the hot spots enhances the Raman scattering signal of the adsorbed pyridine molecule (10 -3 M ). The dependence of SERS signal on the polarization angle of …