Optimization of antireflective coatings with nanostructured TiO2 for GaAs solar cells

This work investigates the effect of titanium dioxide (TiO2) nanostructures on the overall optical performance of gallium arsenide (GaAs) solar cells. The optical properties of three different TiO2 nanostructures shapes namely, cubic, spherical, and pyramidal are studied to minimize the reflectivity of GaAs substrates. The dimensions of these three nanoparticle-shapes are varied in the simulations, and the effects of this parameter-variation on the reflectance is investigated. The simulation was carried using the wave optics module in COMSOL Multiphysics (R). The results indicate that the spherical nanoparticle with a radius of 25 nm gives a reduction of the reflectance down to 9.2 % (compared to the 37.2 % of uncoated GaAs). Furthermore, the pyramidal nanoparticle with both width and length of 50 nm has a nearly similar performance achieving a 9.8 % reflectance. However, the cubic nanoparticles with a width of 100 nm achieved the worst optical performance with a reflectance of 28 %.