Formation of nano-pyramids of layered materials with AFM

We have been able to raise squares of around 2 Angstrom in height of the la yered materials Bi1.6Sb0.4Se3, Bi1.9Sb0.1Se3 and Bi2Se3 by means of contact atomic force microscopy in air. By raising squares on/beneath previously p roduced squares, Mayan-like pyramids have been constructed, each step of th e pyramid being around 2 Angstrom in height. We neither remove matter from the surface nor produce a localized oxidation of the sample; we elevate a p ortion of it. When the surface is oxidized, the AFM cantilever pulls the ox ide off producing holes. The raising of the squares is also possible in a n itrogen atmosphere. (C) 2000 Elsevier Science B.V. All rights reserved.