SURFACE MANIPULATION ON LAYERED ORGANIC-CRYSTALS BY SCANNING FORCE MICROSCOPY

Molecular steps on freshly cleaved (001) surfaces of orthorhombic hydrogen phtalates of monovalent cations (K, Rb, Cs, Tl, NH4) show height differences of 1.3 nm, which agrees with the height of one unit cell in the [001] direction for K, Rb and Tl hydrogen phtalates and half a3-axis periodicity for NH4 hydrogen phtalate. It was possible to remove single (001) lattice planes by the AFM tip during scanning in air. The removed material was deposited at the border of the scanned area. The rate of erosion depends on one hand on the applied force. On the other hand it is controlled by structural differences, which vary with different monovalent cations. Elastic constants could be correlated with a threshold for the loading force necessary for surface damage. On the (001) surface of Rb hydrogen phtalate force maxima show a lateral distance which agrees with the lattice periodicity a1 and a2, thus indicating that single phenyl rings were resolved.