Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 30: Nano Wires: Growth and Characterization
HL 30.1: Talk
Tuesday, March 15, 2011, 10:15–10:30, FOE Anorg
Autocatalytic growth of GaAs nanowires on Si (111) using different SiOx templates — Daniel Rudolph1, Simon Hertenberger1, Xiaodong Wang1,2, •Watcharapong Paosangthong1, Max Bichler1, Gerhard Abstreiter1, Jonathan J. Finley1, and Gregor Koblmüller1 — 1Walter Schottky Institut, TU München, Garching, Germany — 2Pohl Institute of Solid State Physics, Tongji Univ., Shanghai, P.R. China
We investigated the autocatalytic growth of GaAs nanowires (NWs) by molecular beam epitaxy on three different kinds of substrate templates: Si (111) coated with (a) an ultrathin layer of amorphous SiOx, (b) an ultrathin layer of thermal SiO2, and (c) a layer of thermal SiO2 with periodic hole patterns defined by electron beam lithography. For the latter, we have investigated the effect of growth temperature and V/III ratio on the vertical NW growth yield and growth selectivity. The grown NWs were characterized using scanning electron microscopy (SEM), high resolution x-ray diffraction (HRXRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy: SEM images and in-situ reflection high energy electron diffraction studies identified the growth to be mediated by the vapor liquid solid mechanism. A good epitaxial relationship between NWs and the Si substrate is confirmed by HRXRD measurements. TEM analysis revealed the crystal structure to be predominantly zincblende but shows the occurrence of twin boundaries and stacking faults. These results are supported by spatially resolved single NW PL spectroscopy measurements which exhibit the optical signature of zincblende GaAs.