Effect of radio frequency sputtering power on W–TiO 2 nanotubes to improve photoelectrochemical performance

• Published in: Journal of materials research 2012-07, Vol.27 (13), p.1695-1704
• Main Authors: Lai, Chin Wei, Sreekantan, Srimala, San E, Pei
• Format: Article
• Language: English
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2012.163

The present study aims to determine the optimum radio frequency (RF) sputtering power to obtain the desired W–TiO 2 nanotubes for the best photoelectrochemical (PEC) performance. Tungsten (W) was deposited on titania (TiO 2 ) nanotube arrays via RF sputtering technique under different sputtering powers from 50 to 250 W. The optimum content of W on TiO 2 nanotube arrays play a significant role in maximizing the photocurrent generation efficiency to promote charge separation by accumulation of photogenerated electrons. The sputtering power below 180 W exhibited high-ordered and unbroken TiO 2 nanotube arrays. However, the sputtering power over 180 W exhibited broken nanotube arrays and an oxide layer was formed due to the impact of high energy ions accelerated by a high sputtering power. The TiO 2 nanotube arrays sputtered with tungsten at 50 W showed a better photocurrent density (1.55 mA/cm 2 ), with a photoconversion efficiency of 2.2% in the PEC performance among the samples due to the effective charge separation and reduced recombination center in the resultant W–TiO 2 nanotubes.