ATOMIC-FORCE MICROSCOPIC STUDY OF THE SURFACE-MORPHOLOGY OF APATITE FILMS DEPOSITED BY PULSED-LASER ABLATION

Atomic force microscopy (AFM) has been used to study the surface morph ology of apatite films deposited on metallic and polyethylene substrat es by laser ablation using KrF and transversely excited atmospheric CO 2 lasers. The films are found to consist of a smooth apatite coating w ith macroparticles scattered on the surface. A wide variety of macropa rticles, differing in size, shape and roughness, were found and analys ed employing the high spatial resolution of AFM (< 1 nm). We have inve stigated the correlation between the apatite film morphology and the d eposition conditions. Of particular importance are laser fluence, gas pressure, the nature of the target and the substrate temperature. We h ave explained these dependencies on the basis of a theoretical model w hich includes evaporation and a cluster-type laser ablation mechanism. (C) 1997 Elsevier Science Limited. All rights reserved.