SiO₂/TiO₂ double-layer antireflective coating deposited at room temperature for metal/insulator/n-Si/p-Si solar cells

Double-layer antireflective coatings for metal/insulator/n-Si/p-Si solar cells were deposited by the reactive evaporation of Ti₂O₃. Both the outer layer (SiO₂) and the inner layer (TiO₂) were formed at room temperature to prevent metal atoms of the ytterbium electrode from diffusing into the bulk silicon. The refractive indices and transmittance of the films were measured and proved to be in a reasonable range. The reflectance was less than 3% in the wavelength range 570-632 nm. After deposition of the antireflective coating, the short-circuit current increment of 44% at air mass 1 and 46% at air mass 0 illumination were obtained without reducing the open-circuit voltage or the fill factor. This represents a low temperature technique which may provide a two-layer antireflective coating on those photovoltaic devices for which the post-heating processes are not suitable, and which gives superior performance in the UV region.