Antireflecting-passivating dielectric films on crystalline silicon solar cells for space applications

Antireflecting-passivating TiO2-SiO2 double layers on crystalline silicon (Si) were optimized and characterized for space solar cells applications. In the numeric optimization, the MgF2-glass-adhesive-TiO2-SiO2-Si structure was considered. In order to fabricate the TiO2-SiO2 double layer, titanium films were deposited on Si wafers in a vacuum chamber, and then, the sample was annealed in oxygen at high temperatures. Glasses with evaporated MgF2 thin films were bonded to the TiO2-SiO2-Si samples so as to obtain the complete structure. A gain of up to 23.5% in the maximum power is demonstrated for simulated c-Si solar cells using the optimized structure. Characterization of the TiO2-SiO2-Si structure using transmission electron microscopy (TEM) and X-ray reflectivity (XRR) as well as optical characterization are presented.