Effect of tin content in precursor sols on surface and optical properties of tin incorporated titanium oxide amorphous thin films on glass

In this work, adopting simple sol-gel dip coating technique, we deposited tin incorporated amorphous titanium oxide thin films (thickness, 152±2 nm) on pure silica glass from precursor sols (viscosity, 7.5±1.5 cP) with a fixed metal oxide content (six weight percent) by varying tin (II) ethyl hexanoate to titanium isopropoxide molar proportions, R (0 to 0.18) in presence of acetylacetone as sol stabilizer. The films cured at 450 o C in air atmosphere were found to be highly transparent in the visible region and X-ray amorphous. The samples were characterized by spectroscopic ellipsometer for the measurement of physical thickness, refractive index (RI) and extinction co-efficient (k) while the volume porosity was calculated from the measured RI of the films. With increasing tin content in the precursor sols, the root means square surface roughness (RMSSR) as measured from atomic force microscope found increased while the RI decreased but the trend in change of RMSSR found identical with the trend in change of volume porosity and extinction co-efficient of the films. In brief, the RMSSR was found to be closely related to k and volume porosity as well as RI of the films. A co-relation was also drawn between the RMSSR values with the static water contact angle on the surface of the films. Amorphous metal oxide thin films with relatively high refractive index, transparent and low optical loss could be used as optical waveguide materials. Therefore, the film (TS3) deposited from the precursor sol with R, 0.03 showed highest RI value (1.86) with lowest RMSSR and k values. This TS3 film could be used as planar optical waveguide material. Keywords— Sol-gel dip coating, amorphous thin film, surface roughness, ellipsometric analysis, static water contact angle

[1]  A. Bardaoui,et al.  Morphological, structural and ellipsometric investigations of Cr doped TiO2 thin films prepared by sol–gel and spin coating , 2016 .

[2]  Hongtao Lin,et al.  Microstructure, optical properties, and optical resonators of Hf_1-xTi_xO_2 amorphous thin films , 2016 .

[3]  R. Chandra,et al.  Enhanced optical absorbance of hydrophobic Ti thin film: role of surface roughness , 2016 .

[4]  S. Bhadra,et al.  Fabrication, characterization and water wetting behavior of mesoscale 1D/2D periodic structured silica-zirconia sol–gel thin films , 2016 .

[5]  C. Manoharan,et al.  Highly oriented and physical properties of sprayed anatase Sn-doped TiO2 thin films with an enhanced antibacterial activity , 2016, Applied Nanoscience.

[6]  Eric Mazur,et al.  Polycrystalline anatase titanium dioxide microring resonators with negative thermo-optic coefficient , 2015 .

[7]  H. Sirringhaus,et al.  Electronic Structure of Low-Temperature Solution-Processed Amorphous Metal Oxide Semiconductors for Thin-Film Transistor Applications , 2015, Advanced functional materials.

[8]  V. P. Mahadevan Pillai,et al.  Structural, spectroscopic and electrical studies of nanostructured porous ZnO thin films prepared by pulsed laser deposition. , 2014, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[9]  Michal Lipson,et al.  Athermal silicon microring resonators with titanium oxide cladding. , 2013, Optics express.

[10]  R. Mallet,et al.  Optical properties of Nb-doped TiO2 thin films prepared by sol–gel method , 2013 .

[11]  M. Pal,et al.  Effect of precursor sol pH on microstructural, optical and photocatalytic properties of vacuum annealed zinc tin oxide thin films on glass , 2013, Journal of Sol-Gel Science and Technology.

[12]  S. Fathpour,et al.  Submicron optical waveguides and microring resonators fabricated by selective oxidation of tantalum. , 2013, Optics express.

[13]  Eric Mazur,et al.  Submicrometer-wide amorphous and polycrystalline anatase TiO2 waveguides for microphotonic devices. , 2012, Optics express.

[14]  Dong Hun Kim,et al.  On-chip optical isolation in monolithically integrated non-reciprocal optical resonators , 2011 .

[15]  A. J. Frank,et al.  In2S3 Atomic Layer Deposition and Its Application as a Sensitizer on TiO2 Nanotube Arrays for Solar Energy Conversion , 2010 .

[16]  E. Favvas,et al.  Metal-carboxylate interactions in metal-alginate complexes studied with FTIR spectroscopy. , 2010, Carbohydrate research.

[17]  E. H. Faria,et al.  Sol-Gel TiO2 thin films sensitized with the mulberry pigment cyanidin , 2007 .

[18]  Annika Lenz,et al.  Theoretical IR spectra for water clusters (H2O)n (n = 6-22, 28, 30) and identification of spectral contributions from different H-bond conformations in gaseous and liquid water. , 2006, The journal of physical chemistry. A.

[19]  S. Mahanty,et al.  Effect of Sn doping on the structural and optical properties of sol–gel TiO2 thin films , 2004 .

[20]  Vinay Gupta,et al.  Optical waveguiding in amorphous tellurium oxide thin films , 2003 .

[21]  G. Jellison,et al.  Spectroscopic ellipsometry of thin film and bulk anatase (TiO2) , 2003 .

[22]  Jiaguo Yu,et al.  Preparation and characterization of super-hydrophilic porous TiO2 coating films , 2001 .

[23]  R. Olshansky,et al.  Mode Coupling Effects in Graded-index Optical Fibers. , 1975, Applied optics.

[24]  P. Biswas,et al.  Mesoscale Surface Patterned Silica-Titania Sol-Gel Thin Film on Glass , 2014 .