Abstract :
TiO2 thin ®lms were deposited on Si(1 0 0) substrates by pulsed laser deposition technique using Nd:YAG laser. A high
deposition rate of 4.6 nm/min at a laser ¯uence of 6.5 J/cm2 and a pulse repetition frequency of 30 Hz was obtained. The Xray
diffraction patterns of the ®lms were studied as a function of the ®lm thickness. The results show that the 700 nm-thick
®lms consisted of anatase and rutile structure. As ®lm thickness increased, the amount of anatase phase crystal increased,
whereas the rutile remained constant. # 2001 Elsevier Science B.V. All rights reserved
Keywords :
rutile , anataseand brookite. Of these , the anatase crystal isknown as the most active photocatalytic material.When the anatase crystal of TiO2 is irradiated withthe ultra violet light (hn > 3:2 eV) , it can decompose water and/or contaminantsadsorbed on the TiO2 surface.There are many reports on TiO2 thin ®lms depositedby reactive , electron±holepairs are created. Since a hole is a powerful oxidizingagent , pulsed laser deposition , TiO2 , Anatase-crystal , photocatalysis , concern for hygiene in our livingenvironment has increased. A photocatalytic effectusing titanium oxide (TiO2) has been of growinginterest in the ®eld of environmental puri®cation , since it is harmless to humans. There are three differentcrystalline phases of TiO2 , Thin ®lm1. IntroductionIn recent years , namely
