Fabrication and characterization of TiO2 antireflection coatings with gradient-index

Nano-textured anti-reflection films are designed elaborately to improve the transmittance character and to reduce the surface reflection loss. This paper reports the gradient-index TiO2 anti-reflection coatings (ARC) of 50–400 nm were deposited at low pressure (0.6Pa) and target-substrate distance (85mm) on low-iron glass substrates using magnetron sputtering (MSP) assisted with the oblique angle deposition (OAD) technique with different vapor incident angled module. The impact of growth on the film characteristics was studied by in situ spectroscopic ellipsometry (SE), scanning electron microscopy (SEM), Raman spectroscopy and UV-VIS spectrophotometer. Suitable ellipsometric models were built to account for the structural and optical differences. The experimental results were discussed on annealing temperature or incident angle, crystallization parameters of the sub-wavelength nano-structural anti-reflection film. The optimal thickness of the TiO2 ARC was about 250nm. It exhibited a higher transmittance at the visible light regions over a large wavelength range than that of the primitive glass substrate. The value of refractive index for the TiO2 coating was 2.245 at the wavelength of 632.8 nm.

[1]  G. Exarhos.  Substrate signal suppression in Raman spectra of sputter deposited TiO2 films , 1984 .

[2]  Margaret B. Stern,et al.  Binary optics: A VLSI-based microoptics technology , 1996 .

[3]  D. Li,et al.  Spectroscopic ellipsometry analysis of TiO2 films deposited by plasma enhanced chemical vapor deposition in oxygen/titanium tetraisopropoxide plasma , 2012 .

[4]  Arturo A. Ayon,et al.  High efficiency nanotextured silicon solar cells , 2012 .

[5]  Hele Savin,et al.  Review of light-induced degradation in crystalline silicon solar cells , 2016 .

[6]  Zeger Vroon,et al.  Antireflective Coatings for Glass and Transparent Polymers. , 2016, Langmuir : the ACS journal of surfaces and colloids.

[7]  G. Marin,et al.  The effect of argon pressure on the structural and photocatalytic characteristics of TiO2 thin films deposited by d.c. magnetron sputtering , 2006 .

[8]  David Elam,et al.  Aluminum oxide passivated radial junction sub-micrometre pillar array textured silicon solar cells , 2013 .

[9]  M. Anpo,et al.  Preparation of Highly Transparent TiO2-based Thin Film Photocatalysts by an Ion Engineering Method: Ionized Cluster Beam Deposition , 2010 .

[10]  Hyungson Ki,et al.  Pulsed laser deposition of refractive-index-graded broadband antireflection coatings for silicon solar cells , 2016 .

[11]  Li Ji,et al.  Subwavelength nanostructures integrated with polymer‐packaged iii–v solar cells for omnidirectional, broad‐spectrum improvement of photovoltaic performance , 2015 .

[12]  Bai Yang,et al.  Colloidal Self‐Assembly Meets Nanofabrication: From Two‐Dimensional Colloidal Crystals to Nanostructure Arrays , 2010, Advanced materials.

[13]  Seeram Ramakrishna,et al.  Anti-reflective coatings: A critical, in-depth review , 2011 .

[14]  Pichet Limsuwan,et al.  A spectroscopic ellipsometry study of TiO2 thin films prepared by ion-assisted electron-beam evaporation , 2009 .

[15]  Hui Shen,et al.  SiO2 Antireflection Coatings Fabricated by Electron-Beam Evaporation for Black Monocrystalline Silicon Solar Cells , 2014 .

[16]  D. Li,et al.  In situ spectroscopic ellipsometry study of TiO2 films deposited by plasma enhanced chemical vapour deposition , 2013 .

[17]  Xiaohong Wang,et al.  Preparation of ordered mesoporous TiO2 thin film and its application in methanol catalytic combustion , 2013 .

[18]  Mohammad Asif Zaman,et al.  Optimization of multilayer antireflection coating for photovoltaic applications , 2016 .

[19]  Ullrich Steiner,et al.  Self-cleaning antireflective optical coatings. , 2013, Nano letters.

[20]  E. Fred Schubert,et al.  Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection , 2007 .

[21]  H. Zhu,et al.  Optical properties of nanostructured TiO2 thin films and their application as antireflection coatings on infrared detectors. , 2012, Optics letters.

[22]  Agustín R. González-Elipe,et al.  Perspectives on oblique angle deposition of thin films: From fundamentals to devices , 2016 .