Wegscheider, Werner and Schedelbeck, Gert and Bichler, Max and Abstreiter, Gerhard (1999) Atomically precise, coupled quantum dots fabricated by cleaved edge overgrowth. In: Kramer, Bernhard, (ed.) Festkörperprobleme. Advances in Solid State Physics, 38. Vieweg, Wiesbaden, pp. 153-165. ISBN 978-3-540-41575-6.
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Recent progress in the fabrication of quantum dots by molecular beam epitaxy along three directions in space is reviewed. The optical properties of different sample structures consisting of individual quantum dots, pairs of coupled dots as well as of linear arrays of dots are studied by microscopic photoluminescence spectroscopy. The high degree of control over shape, composition and position of the 7×7×7 nm3 size GaAs quantum dots, which form at the intesection of three orthogonal quantum wells, allows a detailed investigation of the influence of coupling between almost identical zero-dimensional objects. In contrast to the inhomogeneously broadened quantum well and quantum wire signals originating from the complex twofold cleaved edge overgrowth structure, the photoluminescence spetrum of an individual quantum dot exhibits a single sharp line (full width at half maximum <70μeV) almost free of background signal. Microscopic photoluminescence excitation spectroscopy directly reveals the discreteness of the energy levels of the zero-dimensional structures and justifies the denomination “artificial atoms” for the quantum dots. It is further demonstrated that an “artifical molecule”, characterized by the existence of bonding and antibonding states can be assembled from two of such “artificial atoms”. The coupling strength between the “artificial atoms” is adjusted by the “interatomic” distance and is reflected in the energetic separation of the bonding and antibonding levels and the linewidths of the corresponding interband transitions.
|Item Type:||Book Section|
|Additional information (public):||Spring meeting of the Arbeitskreis Festkörperphysik, Deutsche Physikalische Gesellschaft; Regensburg; März 23.-27.1998|
|Institutions:||Physics > Institute of Experimental and Applied Physics > Retired Professors > Group Werner Wegscheider|
|Subjects:||500 Science > 530 Physics|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||15 Feb 2010 13:35|
|Last Modified:||15 Feb 2010 13:35|