Controlled Pore Formation on Mesoporous Single Crystalline Silicon Nanowires: Threshold and Mechanisms

Figure 4

(a) Medium boron-doped Si (ρ = 14–23 Ωcm), etched for  h,  M,  M. SEM image of a slightly tilted silicon wafer after the etching illustrating the etching along the -directions, perpendicular and parallel to the wafer’s surface, which has the (100)-orientation. -directions are indicated with white dashed lines. (b) SEM image of a single bundle of silicon nanowires from highly boron-doped silicon (ρ < 0.01 Ωcm); marked boxes are magnified in (c) showing the cylindrical porous surface structure and (d) interconnected pores forming meander-like trenches on the porous surface.

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