We demonstrate laterally aligned and catalyst-free GeSi nanowires (NWs) via self-assembly of Ge on
miscut Si (001) substrates toward the [100] direction by an angle θ (θ < 11°). The NWs are bordered by
(001) and (105) facets, which are thermodynamically stable. By tuning the miscut angle θ, the NW height
can be easily modulated with a nearly constant width. The thickness of the wetting layer beneath the NWs
also shows a peculiar behavior with a minimum at around 6°. An analytical model, considering the vari-
ation of both the surface energy and the strain energy of the epilayer on vicinal surfaces with the miscut
angle and layer thickness, shows good overall agreement with the experimental results. It discloses that
both the surface energy and stain energy of the epilayer on vicinal surfaces can be considerably affected
in the same trend by the surface steps. Our results not only shed new light on the growth mechanism
during heteroepitaxial growth, but also pave a prominent way to fabricate and meanwhile modulate later-
ally aligned and dislocation-free NWs.
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Funding Info:
Major State Basic Research Project (no. 2011CB925601) of China; A*STAR (SERC grants no. 132 550 4103 and 132 550 4106) as well as computing resources from A*STAR A*CRC.