Periodically Changing Morphology of the Growth Interface in Si, Ge, and GaP Nanowires

C-Y Wen, Purdue University
J. Tersoff, IBM Corp, Yorktown Hts, NY
K. Hillerich, Lund Univ,Lund, Sweden
M.C. Reuter, IBM Corp, Yorktown Hts, NY
J. H. Park, Univ Calif Los Angeles
S. Kodambaka, Univ Calif Los Angeles
Eric Stach, Purdue University
F.M. Ross, IBM Corp,Yorktown Hts, NY

Abstract

Nanowire growth in the standard < 111 > direction is assumed to occur at a planar catalyst-nanowire interface, but recent reports contradict this picture. Here we show that a nonplanar growth interface is, in fact, a general phenomenon. Both III-V and group IV nanowires show a distinct region at the trijunction with a different orientation whose size oscillates during growth, synchronized with step flow. We develop an explicit model for this structure that agrees well with experiment and shows that the oscillations provide a direct visualization of catalyst supersaturation. We discuss the implications for wire growth and structure.

Discipline(s)

Nanoscience and Nanotechnology