Sputtered Ta2O5 antireflection coatings for silicon solar cells

Abstract

Ta2O5 thin films were deposited onto monocrystalline silicon surfaces by magnetron reactive sputtering. When the Ta2O5 films are employed as antireflection coatings, the reflectance of the original silicon surface diminishes from about 30% to approximately 3%. At the same time, a very low absorption coefficient (less than 103 cm-1) for the Ta2O5 films below their fundamental absorption edge (hv < 4.2 eV) is obtained from reflectance and transmittance spectra of Ta2O5 deposited onto quartz substrates. Finally, the technique of reactive sputtering is considered from the point of view of preparing antireflection coatings for solar cells.