Publication
Physical Review Letters
Paper
Periodically changing morphology of the growth interface in Si, Ge, and GaP nanowires
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. © 2011 American Physical Society.