Large carbon cluster ion formation by laser ablation of polyimide and graphite

Abstract

Polyimide is studied by laser ablation using 266 nm radiation. Ions formed in the ablation are detected using a Fourier transform mass spectrometer. Mass spectra of graphite are also obtained under the same experimental conditions. The mass spectra from polyimide show large intensities of high-mass carbon cluster ions ( m/e > 800 amu), similar in composition to those observed by laser ablation of graphite under some conditions. For ablation of polyimide using higher laser fluence, lower-mass distributions of ions are also observed. The craters formed by the laser ablation of both polyimide and graphite are measured in order to find the volume of material ablated per pulse, which is used to estimate the particle density in the laser-generated plasma. The results are shown to be consistent with the growth of the high-mass ions by gas phase reactions.