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Browsing by Author "Tischler, J. G."

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    Dynamics of photoexcited carriers and spins in InAsP ternary alloys
    Meeker, M. A.; Magill, Brenden A.; Merritt, T. R.; Bhowmick, M.; McCutcheon, K.; Khodaparast, Giti A.; Tischler, J. G.; McGill, S.; Choi, S. G.; Palmstrom, C. J. (AIP Publishing, 2013-06)
    The recent rapid progress in the field of spintronics involves extensive measurements of carrier and spin relaxation dynamics in III-V semiconductors. In addition, as the switching rates in devices are pushed to higher frequencies, it is important to understand carrier dynamic phenomena in semiconductors on femtosecond time-scales. In this work, we employed time and spin resolved differential transmission measurements; to probe carrier and spin relaxation times in several InAsP ternary alloys. Our results demonstrate the sensitivity of the spin and carrier dynamics in this material system to the excitation wavelengths, the As concentrations, and temperature. (C) 2013 AIP Publishing LLC.
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    Photoluminescence lineshape and dynamics of localized excitonic transitions in InAsP epitaxial layers
    Merritt, T. R.; Meeker, M. A.; Magill, Brenden A.; Khodaparast, Giti A.; McGill, S.; Tischler, J. G.; Choi, S. G.; Palmstrom, C. J. (American Institute of Physics, 2014-05-21)
    The excitonic radiative transitions of InAsxP1-x (x = 0.13 and x = 0.40) alloy epitaxial layers were studied through magnetic field and temperature dependent photoluminescence and time-resolved photoluminescence spectroscopy. While the linewidth and lineshape of the exciton transition for x = 0.40 indicate the presence of alloy broadening due to random anion distribution and the existence of localized exciton states, those of x = 0.13 suggest that this type of compositional disorder is absent in x = 0.13. This localization is further supported by the behavior of the exciton transitions at low temperature and high magnetic fields. InAs0.4P0.6 exhibits anomalous "S-shaped" temperature dependence of the excition emission peak below 100K as well as linewidth broadening at high magnetic fields due to the compression of the excitonic volume amid compositional fluctuations. Finally, photoluminescence decay patterns suggest that the excitons radiatively relax through two channels, a fast and a slow decay. While the lifetime of the fast decay is comparable for both compositions (similar to 30 ps), that of the slow decay increases from 206 ps to 427 ps as x increases from 0.13 to 0.40, attributable to carrier migration between the localization states of InAs0.4P0.6. (C) 2014 AIP Publishing LLC.