Dresden 2011 – scientific programme

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KR: Fachgruppe Kristallographie

KR 7: Crystallography in Materials Science (jointly with DF)

KR 7.2: Talk

Thursday, March 17, 2011, 14:45–15:00, HSZ 101

The Crystal structure of InAs nanorods grown onto Si[111] substrate — •Anton Davydok¹, Andreas Biermanns¹, Steffen Breuer², Manos Dimakis², Lutz Geelhaar², and Ullrich Pietsch¹ — ¹Festkörperphysik, Universität Siegen, Walter-Flex-Str. 3,57072, Siegen, Germany — ²Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7,10117 Berlin, Germany

Nanowires are of particular interest due to the ability to synthesize heterostructures in the nanometer range. It was found that nearly any AIIIBV semiconductor material can be grown as NWs onto another AIIIBV or group IV [111] substrate independent from lattice mismatch. We presented an X-ray characterization of InAs NRs on Si [111] grown by assist free MBE method. Lattice mismatch of this materials is 11%. For study of strain realizing we concentrated our research on initial stages of growth process investigating samples set with different growth time. Using synchrotron radiation we have performed experiments in symmetrical and asymmetrical out-of plane scattering geometry and grazing-incidence diffraction. Combining the results we were able to characterize the transition between silicon silicon substrate and InAs NWs. We find in-plane lattice mismatch of -0.18% close to the interface compared to InAs bulk material. With help of micro-focus setup we are able measure structural paramters of single NWs to determine the strain accomodation as function of NW size. In particular using asymmetric wurzite-sensitive reflections under coherent beam illumination we could quantify the number of stacking faults. In the talk we present details of the analysis and first simulation results.