Terawatt laser system irradiation of carbon/tungsten bilayers

Using the original themionic vacuum arc method (TVA), carbon films with the thickness of about 2500 nm were coated on top of 200 nm tungsten films deposited on tine grain graphite substrates. The carbon/tungsten hi layers vt ere irradiated using a terawatt laser system (TEWALAS), 360 ps and 100 fs pulse duration, 110-150 mJ pulse energy. The analysis of the selected area electron diffraction (SHED) pattern allowed the identification of rhomhoedral structures corresponding to diamond. Th e Raman scattering measurements were also performed on the produced craters and the specific peak at 1330 cm(-1) corresponding to diamond was observed. The C-C sp(3) bonding content increased to 39.4% in the irradiated region compared to 30.8% in the "as deposited" zone, as shown by XPS. The craters produced by the laser irradiation were morphologically studied using optical imaging and scanning electron microscopy. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim