Optical properties of nanostructured WO3 thin films by GLancing Angle Deposition: Comparison between experiment and simulation

• WO3 thin films were sputtered by GLancing Angle Deposition.
• Inclined columnar and zigzag features were produced.
• Refractive index and birefringence were simulated by MEEP.
• Incidence angle and number of zigzags tune the optical properties.
• Anisotropic structure leads to optimized refractive index and birefringence.

Optical properties (refractive index and birefringence) of WO3 thin films exhibiting columnar and zigzag nanostructures deposited by GLancing Angle Deposition are analyzed. The influence of the incident angle α of the sputtered particles and the number of zigzags N on these optical properties is determined. The experimental results show that refractive index of zigzag nanostructures evolves with the number of zigzags from nN = 0.5 = 2.02 to nN = 8 = 2.05 through a maximum nN = 4 = 2.29. The birefringence of columnar structures exhibits a similar trend when α changes from 0 to 80°. Birefringence of columnar and zigzag structures reaches both a maximum when α = 50° (Δnα = 50° = 0.025). Experimental results favorably agree with the simulated ones calculated by means of the MEEP FDTD code.