Optical, Photocatalytic and Wetting Behavior of GLAD N2‐TiO2 Films

• Published in: Physica status solidi. A, Applications and materials science Vol. 216; no. 14
• Main Authors: De, Rajnarayan, Haque, S. Maidul, Misal, Jitendra S., Shinde, Deepak D., Prathap, Chilakala, Polaki, Shyam R., Singh, Ranveer, Som, Tapobrata, Rao, K. Divakar
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 24.07.2019
• Subjects: antireflection; band gap; Coatings; Contact angle; Deposition; Doping; Flow velocity; glancing angle deposition; Nanowires; Photocatalysis; Reduction; Refractivity; Surface structure; TiO2 coatings; Titanium dioxide; Wetting
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201900021

E‐beam evaporated N2‐doped TiO2 vertical nanowires are fabricated using glancing angle deposition technique. Doping is carried out during the deposition process by external supply of N2 gas at different flow rates viz. 0, 5, 10, 20 sccm. The effect of doping concentration on various properties of the coatings is studied in detail. Refractive index value is found to be increased from 1.374 to 1.604 with increase in N2­ flow rate into the deposition chamber. Simultaneous reduction in average film transmittance (≈95–≈92%) is also observed in the visible wavelength range. Substantial reduction in optical band gap (3.85–3.43 eV) value of the coating is also noted. Surface structure of the coatings is also found to be strongly dependent on doping concentration. Samples prepared with highest doping percentage is found to have lowest RMS roughness (≈2.3 nm), void percentage (≈22%), and agglomerated grain structures. Water wetting study reveals increase in water contact angle of the samples with N2 doping. All the samples are found to be photocatalytic in nature with improved efficiency of doped samples. The present original paper reports a systematic investigation on various properties of TiO2 nanowire structures with nitrogen doping. The coatings show modification in optical properties with doping concentration along with enhancement in photocatalytic action, alteration in surface nature, and change in wetting behavior. The overall study suggests the applicability of the coatings in fabricating multi‐functional devices with anti‐reflecting and photocatalytic properties.