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Descripción
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| The Photonic and Semiconductor Nanophysics group in the Technical University of Eindhoven is probably the world-leading group in using the cross-sectional scanning tunneling microscopy (X-STM) technique to study semiconductor nanostructures. This technique, available only in a few laboratories in the world, provides unique information at the atomic scale. A set of samples consisting of the quaternary GaAsSbN bulk material grown at different growth rates and GaAsSb/N superlattices with different period thicknesses were measured by X-STM at a low temperature X-STM system. Under such conditions pressures below 5 x 10-13 torr are reachable, allowing the preservation of a clean surface for weeks and providing an atomic resolution. X-STM measurements provided direct information on the Sb and N concentration and distribution in the quaternary GaAsSbN, since the three group V atoms As, Sb, and N, give a very different contrast and can be counted at the single atom level. Additionally, In the case of the superlattice structures, the GaAsSb/GaAsN interfaces were also finely characterized, drawing information on the degree of the elements? segregation. The low working temperature of this system also allowed the realization of STM spectroscopy, giving information concerning the local density of states, associated to the presence of both Sb and N, and the possible electronic coupling in the superlattice structures. The numerous conclusions drawn from the different XSTM analyses were essential for the understanding of the impact of the growth conditions on the Sb-N incorporation as well as for a proper sample design intended for improved efficiencies of solar cell devices. | |
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Internacional
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Si |
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Lugar
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Eindhoven, the Netherlands |
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Tipo
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Fecha inicio
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11/09/2015 |
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Fecha fin
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11/12/2015 |