Laser induced desorption of molecular fragments from the surface of Cu-phtalocyanine thin films

Laser-induced desorption from thin films (approx. 500 nm thick) of Cu-phtal ocyanine cast from solution on a glass substrate was investigated. The mass -spectra and dependence of desorption intensities on incident irradiation e nergy were studied by means of time-of-flight mass-spectrometry. 20 ns puls e laser irradiation was used at 532 nm and 1064 nm wavelengths. According t o the absorption spectrum of the Cu-phtalocyanine films the wavelengths cor respond to bandgap and sub-bandgap excitation of the films, respectively. D esorption of Cu-phtalocyanine molecules, their fragments, including Cu atom s was observed when laser energy exceeded 0.05 J/cm(2) pulse and 0.4 J/cm(2 ) pulse thresholds in case of the bandgap and the sub-bandgap excitation, r espectively. Cu atoms component was the most intensive in the desorption fl ow. The phenomena observed are discussed in terms of the incident energy ab sorption in the aromatic system and via the localized states of the Cu-phta locyanine films under study.