3D compositional analysis at atomic scale of InAlGaAs capped InAs/GaAs QDs

International audienceThe 3D compositional distribution at the atomic-scale of InAs/GaAs quantum dots (QDs) with an InAlGaAs capping layer has been obtained by atom probe tomography. A heterogeneous distribution of Al atoms has been revealed. An Al-rich ring around the QDs has been observed. A detailed analysis of the QDs composition evidences a high degree of In/Ga intermixing, with an increasing In gradient in the growth direction. The atomic scale analyses of these nanostructures are essential to understand their functional properties

Atom Probe Tomography Analysis of InAlGaAs Capped InAs/GaAs Stacked Quantum Dots with Variable Barrier Layer Thickness

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Model reduction - an algebraic, geometric and operator theoretic approach Final scientific report

Available from TIB Hannover: F98B1713 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEGerman-Israeli Foundation for Scientific Research and Development (GIF), Oberschleissheim (Germany)DEGerman

Some analytical properties of #gamma#-convex functions on the real line

This paper deals with analytical properties of #gamma#-convex functions on the real line, which are defined as those f satisfying the inequality f(x'_1)+f(x'_2)#<=#f(x_1)+f(x_2) for x'_i element of [x_1, x_2], parallel x_i-x'_i parallel =#gamma#, i=1,2, whenever parallel x_1-x_2 parallel >#gamma# for some given positive #gamma#. This class contains all convex functions and all periodic functions with period #gamma#. In general, #gamma#-convex functions do not have such good properties as convex functions. For instance, there exist #gamma#-convex functions which are nowhere continuous or totally unbounded. But #gamma#-convex functions possess so-called conservation properties, i.e., properties which remain true on every bounded interval, or even on the entire domain, if only they hold true on an arbitrary closed interval with length #gamma#. It is shown that boundedness, bounded variation, integrability, continuity and differentiability almost everywhere are some conservation properties of #gamma#-convex functions on the real line. Further on, #gamma#-convex functions also have infection properties, i.e., properties which certainly infect to other places, once appear somewhere, for example, discontinuity. Besides, some equivalent characterizations of #gamma#-convexity are given. Additionally, some ways for generating and representing #gamma#-convex functions are described. (orig.)Available from TIB Hannover: RR 1606(95-14) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman