Figure 6
Wire structures and MacEtch rates as a function of the deposition rate and thickness of the Au catalyst film.
MacEtch conditions can be divided into three distinct regions. In Region 1 (R1, blue circles at bottom), Si nanowires can be obtained due to the fact that the Au film consists of a network of isolated nanoparticles. The conditions of Region 2 (R2, red circles at top left) are sufficient to produce Si microwires, but high aspect ratio structures cannot be obtained due to the non-uniform etch rate. In Region 3 (R3, red circles a top right), the vertically aligned Si microwires with a high aspect ratio were obtained using an Au film with a thickness of 30 to 40 nm and a fast deposition rate (≥3 Å/s) in Region 3.
