Effects of Oxygen Working Pressure on Structural and Optical Properties of TiO2 Films Grown on Glass Substrate

概要

論文の詳細を見る
TiO2 thin films were grown on glasses using a pulsed laser deposition (PLD) system. In order to fully clarify the correlation between their properties and the working pressure of oxygen at which they are grown, a wide range of pressures from 10 to 75 mTorr was investigated. The optical gap of TiO2 films gradually increased from 3.3 to 3.41 eV with increasing working pressure up to 25 mTorr but became notably large at 50 mTorr and continued to increase significantly with further pressure increase. X-ray diffraction (XRD) results showed that the films grew preferentially along the (101) orientation. (101) peak intensity increased as working pressure increased up to 25 mTorr. However, the peak intensity began to decrease and eventually disappeared with further increase in working pressure, indicating structural changes from crystalline to disorderlike phases. The TiO2 films showed high crytallinity with large grains at 25 mTorr but showed a columnar structure with small grains at 75 mTorr. The growth mode of TiO2 thin films was observed to change from lateral to islandlike growth in response to the increase in working pressure. The correlation between oxygen pressure and film properties is discussed in terms of structural and compositional changes.
2012-09-25