Fig. 4

Schematic view of pre-etched patterns in oxide layer a on Si{111} surface with b quantitative details. Zoomed-in view of pre-etched pattern c before and d after wet anisotropic etching. The line OA indicates where the centres of all circles lie on 〈110〉 direction and therefore the notches of hexagon pattern perfectly aligns along 〈110〉 direction. The lines O′A′ and O″A″ are parallel to OA indicate the misalignment of the notches when the centres of all circles do not lie on 〈110〉 direction