Structural and photocatalytic properties of TiO2 films fabricated on silicon substrates by MOCVD method

Silicon ( 111) and Silicon(100) were employed for fabrication of TiO2 films by metal organic chemical vapor deposition( MOCVD). Titanium(IV) isopropoxide(Ti[O(C3H7)4] ) was used as a precursor. The as-deposited TiO2 films were characterized with FE-SEM, XRD and AFM. The photocatalytic properties were investigated by decomposition of aqueous Orange II . And UV-VIS photospectrometer was used for checking the absorption characteristics and photocatalytic degradation activity. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, the photoactivities varied following a shape of "M": at lower(350 degrees C ), middle(500 degrees C ) and higher(800 degrees C ) temperature of deposition, relative lower photodegradation activities were observed. At 400 degrees C and 700 degrees C of deposition, relative higher efficiencies of degradation were obtained, because one predominant crystallite orientation could be obtained as deposition at the temperature of two levels, especially a single anatase crystalline TiO2 film could be obtained at 700 degrees C.