Advanced Research Laboratories (ARL)

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Browsing Advanced Research Laboratories (ARL) by Author "Akça, İmran B."

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    Comparison of electron and hole charge-discharge dynamics in germanium nanocrystal flash memories
    (AIP Publishing, 2008-02) Akça, İmran B.; Dâna, Aykutlu; Aydınlı, Atilla; Turan, R.
    Electron and hole charge and discharge dynamics are studied on plasma enhanced chemical vapor deposition grown metal-oxide-silicon germanium nanocrystal flash memory devices. Electron and hole charge and discharge currents are observed to differ significantly and depend on annealing conditions chosen for the formation of nanocrystals. At low annealing temperatures, holes are seen to charge slower but to escape faster than electrons. They discharge slower than electrons when annealing temperatures are raised. The results suggest that discharge currents are dominated by the interface layer acting as a quantum well for holes and by direct tunneling for elec-trons.
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    Electro-optic and electro-absorption characterization of InAs quantum dot waveguides
    (Optical Society of America, 2008-03) Akça, İmran B.; Dana, Aykutlu; Aydınlı, Atilla; Rossetti, M.; Li, L.; Fiore, A.; Dağlı, N.
    Abstract Optical properties of multilayer InAs quantum dot waveguides, grown by molecular beam epitaxy, have been studied under applied electric field. Fabry-Perot measurements at 1515 nm on InAs/GaAs quantum dot structures yield a significantly enhanced linear electro-optic efficiency compared to bulk GaAs. Electro-absorption measurements at 1300 nm showed increased absorption with applied field accompanied with red shift of the spectra. Spectral shifts of up to 21% under 18 Volt bias was observed at 1320 nm. (C) 2008 Optical Society of America.