SFM and SEM investigation of CdS layers from Langmuir-Blodgett film templates

The morphology of ultrathin layers of CdS nanocrystals from cadmium arachidate Langmuir-Blodgett (LB) film templates has been investigated by means of scanning force and scanning electron microscopies (SEM). Consistently with previous Brewster angle microscopy investigations, low resolution electron micrographs reveal a flat film surface characterized by steps due to the difference in the number of precursor layers. Scanning force microscopy (SFM) allows one to get information on the mesoscopic and atomic film structure. While in the range 1-10 mu m the film appears to be formed by a series of flat platforms, often shaped like triangles and sometimes superorganized in larger needle-like structures, in the hundred nanometer scale an irregular granular structure appears. Finally, performing zooms onto flat platforms, the CdS hexagonal lattice appears, revealing a lattice periodicity of 0.42 nm, in agreement with the bulk value. (C) 1998 Elsevier Science S.A. All rights reserved.