Photoelectric properties of nanostructural carbonaceous films containing Ni nanocrystals investigated by picosecond laser-induced photoelectric charge emission

Abstract

We present results of photoelectric properties of carbonaceous films containing metallic nanocrystals, investigated by pulsed laser-induced photoelectric charge emission and in situ work function measurements. Samples are multiphase carbonaceous thin films composed of Ni nanocrystals embedded in a graphite–fullerene matrix. Photoelectric measurements are performed in a vacuum chamber. Picosecond laser-induced photoelectric charge measurements are performed at 213 nm at a low laser intensity (∼1 MW cm−2). At this intensity, surface cleaning effects are clearly demonstrated by a photoelectric charge increase during pulsed irradiation correlated to an in situ photoelectric threshold lowering. Surface contamination is also observed after the exposition of samples to the ambient air. MicroRaman measurements are carried out before and after laser irradiation in order to control that no structural changes have occurred under the pulsed laser beam.