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search.filters.applied.f.access: openAccess × End date: 2019 × Start date: 2016 × End date: 2009 × Start date: 2000 × Type: article × WGL Institute: PDI ×

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    Nitrogen-enhanced indium segregation in (Ga,In)(N,As)/GaAs multiple quantum wells grown by molecular-beam epitaxy
    (Milton Park : Taylor & Francis, 2007) Luna, E.; Trampert, A.; Pavelescu, E.-M.; Pessa, M.
    Transmission electron microscopy (TEM) is used to determine the composition of quaternary (Ga,In)(N,As) quantum wells (QWs). Through a combined analysis of the chemically sensitive (002) dark-field (DF) images and the lattice-resolving high-resolution TEM images, the local distributions of nitrogen and indium in the growth direction are determined. In particular, we are able to directly detect the existence of indium segregation in (Ga,In)(N,As) QWs. A comparison with the indium distribution profile in the nitrogen-free (In,Ga)As QWs, grown under similar conditions, revealed that incorporating N into the alloy enhanced indium segregation.
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    Enhanced spin coherence via mesoscopic confinement during acoustically induced transport
    (Milton Park : Taylor & Francis, 2008) Stotz, J.A.H.; Hey, R.; Santos, P.V.; Ploog, K.H.
    Long coherence lifetimes of electron spins transported using moving potential dots are shown to result from the mesoscopic confinement of the spin vector. The confinement condition to control electron spin dephasing is governed by the relation between the characteristic spin–orbit length of the electron spins and the dimensions of the dot potential, which governs the electron spin coherence lifetime. The spin–orbit length is a sample-dependent parameter determined by the Dresselhaus contribution to the spin–orbit coupling and can be predictably controlled by varying the sample geometry. We further show that the coherence lifetime of the electron spins is independent of the local carrier densities within each potential dot, which suggests the possibility of coherent, long-range transport of single electron spins.