Characterization of TiO₂ antireflection coatings elaborated by APCVD for monocrystalline silicon solar cells

Abstract

In this work, high quality titanium dioxide thin films were grown by an efficient, less expensive and rapid method of Atmospheric Pressure Chemical Vapor Deposition (APCVD) from TiCl4 precursor for application as antireflection coatings on monocrystalline silicon solar cells with the aim to reduce the front surface reflection losses. The microstructural, electrical and optical properties of the produced coatings were successfully characterized by Atomic Force Microscopy (AFM), Four Point Probe (FPP) and Spectroscopic Ellipsometry (SE). The produced coatings were uniform, homogenous and relatively smooth. The density of the deposited TiO2 films is found to be ρ ′ = 3.11 g/cm3. The porosity of these films is estimated to ϕ = 24%. A perfect agreement between the AFM results and the ellipsometric results was confirmed. The refractive index of our TiO2 thin films was found to be n = 2.25 at the wavelength λ = 550 nm, with a thickness of 56.2 nm. Our results show the possibility to fabricate TiO2 layers with the optimal optical qualities required for antireflection coating, using the APCVD technique. An excellent agreement is reached between our experimental results and calculated results for TiO2 single‐layer antireflection coating on monocrystalline silicon solar cells. The electrical resistivity of the deposited TiO2 films at 450°C annealed at 450°C for 1 hr, was found to be ρ = 1.7 × 10‐3 Ω.cm. The sheet resistance of our TiO2 films was equal to R□ = 303 Ω/□. The obtained results demonstrate the real opportunity of the APCVD technique to prepare high quality antireflection coatings for high efficiency silicon solar cells. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Study of the Relationships Between Optical and Physical Properties for Nanostructure TiO2 Thin Film

“…The conclusion that various of the refractive index with a wavelength of the deposited TiO 2 / glass is explained in gure 5. TiO2 refractive index was found to be n = 2.49 at the λ = 550 nm at 400 o C agreement this result with reference [27] for TiO 2 lms by PLD technique.…”

“…The index of refractive for TiO2 is rising with high temperatures. From gure conclude the refractive index at wavelength λ = 550 nm is equal ( 2.11, 2.88, 2.80 and 2.49) of the lms with substrate temperatures of (100, 200, 300 and 400 ) o C respectively, coincident results with reference [27].…”

Non-Vacuum Process for Production of Crystalline Silicon Solar Cells

“…The lowest average reflectance of 21.41% was achieved by spray-deposited TiO 2 coating with a thickness of 60.6 nm. These values are in a relative agreement of calculated value of 56.8 at the wavelength of 550 nm for the refractive index of TiO 2 as 2.2 [20]. The bottom of reflectance valley shifted to higher wavelength with increasing the solution volume from 2 to 12 mL, gradually which shows the thickness dependence of reflection as well.…”

In situ mass spectrometry analysis of chemical vapour deposition of TiO2thin films to study gas phase mechanisms

“…Atmospheric pressure CVD (APCVD) is the most basic method of chemical vapour deposition, simply heating precursors to roughly half of its boiling point so that a vapour is evolved, then pushing the vapour to a heated reactor where it decomposes, depositing a film onto a substrate. 3 This method is commonly employed to deposit functional metal oxide thin films from simple molecular precursors, including TiO2, [4][5][6] VO2(M), [7][8][9] SnO2, [10][11][12] Fe2O3, 13 WO3, 14,15 ZnO, [16][17][18] α-Al2O3, 19,20 as well as many others. 21 Despite widespread use in the deposition of metal oxide coatings, little is known about reactions that occur within the gas phase during the deposition of the thin film.…”