Figure 4

Cross-sectional TEM and HRTEM images of NR. (a) Cross-sectional TEM image of the saw-like edged NR. (b-d) Cross-sectional HRTEM images of the three regions (the end part of the saw-like edge, the middle part of the saw-like edge, and the part of the basal nanowire) indicated in panel (a). The insets of (b-d) show diffractograms of the Si region in the box in each part. These indicate that the basal nanowire was grown along < 110 > direction and that the Si nanosaw/NR is bi-crystalline containing a single {111} twin. (e) Schematic diagram of the projected shape and facets of the basal nanowire part. (f) Schematic showing the formation of the Si NR.