Photo-induced hydrophilic properties of reactive RF magnetron sputtered TiO2 thin films

✍ Scribed by Junjie Xiong; Sachindra Nath Das; Sungyeon Kim; Jinhyong Lim; Hyun Choi; Jae-Min Myoung

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 576 KB
• Volume: 204
• Category: Article
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2010.04.001

✦ Synopsis

Photo-induced hydrophilic

Oxygen flow ratio Self cleaning TiO 2 thin films were deposited by reactive radio frequency magnetron sputtering of Ti target at low working pressure (1 mTorr) and various O 2 and Ar flow ratios (R O2 = O 2 /(O 2 + Ar)). Properties of TiO 2 films were measured by field emission scanning electron microscopy, atomic force microscopy, X-ray diffractometry, UV-VIS transmission spectroscopy, X-ray photoelectron spectroscopy and evaluated by contact angle analysis. Well defined columnar structure with rough surface was obtained at relatively lower R O2 . As R O2 increased, the oxygen vacancies in the films decreased and the stoichiometric ratio of O/Ti changed from 1.79 to 1.98. Transition from anatase to rutile phase was observed with increase in R O2 . The optical bandgap showed a red shift with increase in R O2 . In addition, the film with co-existing of rutile and anatase showed a high Urbach tail. Lower R O2 resulted in higher photo-hydrophilicizing efficiency due to the change in morphology, structure and composition. However, very low R O2 (less than 10%), which led to transition mode, resulted in poor photo-hydrophilicizing efficiency.