Ambient room temperature dense plasma focus deposition of nano phase TiO<inf>2</inf> thin films on polymeric materials

Abstract

Summary form only given. Successful deposition of nano-phase crystalline TiO2 thin films on polymeric substrates, polymethylmethacrylate (PMMA) and knitted polyethylene (PE) at room temperature was achieved using the dense plasma focus (DPF) device. Deposition was achieved using argon- oxygen gas mixture in the ratio of 9:1 after evacuating the chamber to a base pressure of 10-5 mbar. The working gas pressure and voltage were kept at 3 mbar and 10 kV respectively throughout the experiment .XRD and Raman spectroscopy confirm the presence of crystalline anatase and rutile on as deposited thin film samples. Films deposited using a different number of plasma focus shots or deposited at different distances from the anode exhibit different morphological properties. The films deposited on the polymer surfaces were more adherent when compared with films on glass slides and on silicon substrates in a scratch test. SEM micrographs confirm the presence of nano-sized grains at smaller number of deposition shots or higher distance of deposition. The tendency to agglomerate was found to increase either with the number of deposition shots or with a decrease in the anode-substrate deposition distance. The results have been explained on the basis of ion emission characteristics of the dense plasma focus device.