Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 51: Poster IV

HL 51.30: Poster

Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D

MBE-growth and analysis of Si and Ge nanowires and corresponding heterostructures — •Andreas Wolfsteller, Pratyush Das Kanungo, Trung-Kien Nguyen-Duc, Gerhard Gerth, Nikolai Zakharov, Peter Werner, and Ulrich Gösele — Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale), Germany

Nanowires (NW) are expected to be building blocks for future electronic and optical devices, e. g. new field-effect transistors or chemical sensors. The most common growth mechanism for the synthesis of epitaxial free-standing nanowires is the vapour-liquid-solid (VLS) mechanism, which can in principle also be applied to grow Si NW and nanowire-based SiGe heterostructures by molecular beam epitaxy (MBE) as it has been reported earlier [1]. Now also Ge NW have been grown and the use of Au colloids with 15-18 nm diameter as precursors for NW growth instead of the former deposition of a thin Au film drastically decreased the thickness of both the Si and Ge NW due to the prevention of Ostwald-ripening. Concerning the nanowire-based SiGe heterostructures, by varying the temperature during growth the maximum Ge concentration in selected layers within the NW could be improved from 10% to 26%. Furthermore we present the results from electrical (I-V) and optical (PL) measurements on Si and Ge NW and corresponding nanowire-based heterostructures. The morphology, crystal structure and chemical composition was analyzed by TEM, SEM, and EDX.

[1] N. D. Zakharov et al., J. Cryst. Growth 290 (2006) 6