The change of the surface morphology of organic films by laser pulses

In this work by the means of atomic force microscopy (AFM) was investigated the morphology of thin films of organic molecules based on perylene and MPc, irradiated by laser radiation. It is known that the action of nanosecond laser pulse leads to a fragmentation of organic films of perylene, and MnPc derivatives. In this connection, the task was to study the surface topography of the films of perylene and MPc by the means of AFM after irradiation of them by pulsed laser radiation of nanosecond duration. The radiation source used laser with photon energy of 2.34 eV and a pulse width of 10 ns. The films were deposited on the surface of the GaAs (100) using a Knudsen cell in a vacuum 10 Pa. The study of the surface topography of the irradiated films was carried out under the forvacuum (10 Pa) using an atomic force microscope. It was discovered that modification of organic films, which manifests itself as a change in the morphology of the surface, takes place. In particular, for the first time found that the effect of laser radiation leads to an irreversible change in the topography of the surface, which is not observed with optical instruments. The comparative analysis of topography measurements of the films parts of the surface before and after laser irradiation shows, that from a certain threshold power density of 2.4 mJ/cm, the removing of the layer from the surface of the organic film takes place, whereby the film thickness is reduced by approximately 20 nm. © (2014) Trans Tech Publications.