Figure shows the edge area with four BN layers (see also the line profile in Fig. ). Any moiré patterns and the related rotational stacking faults are not present at the edge, indicating that the edges are not folded back bur rather exhibit the smallest possible scroll, as often observed in the edge structures of high-quality free-standing graphene layers. All the above results demonstrate that as far as the nontwisted hBN layers are concerned, atomically clean, flat and strain-free samples can be obtained by the present exfoliation procedure.