Exploring the deposition of oxides on silicon for photovoltaic cells by pulsed laser deposition

Since most commercially available solar cells are still made from silicon, we are exploring the introduction of passivating qualities in oxides, with the potential to serve as an antireflection coating. Pulsed laser deposition (PLD) was used to deposit TiO2 and SrTiO3 coatings on silicon substrates. Introduction of passivating qualities was achieved by changing the deposition ambient and/or deposition set-up (not placing the substrate in the customary position parallel to the target surface but perpendicular to it). This change in deposition set-up resulted in a remarkable increase in passivating qualities for TiO2 coatings. The plasma shape and place of the substrate in the plasma influenced greatly properties as smoothness, thickness distribution and passivating quality. The particle energy on arrival at the substrate and the oxygen content at the surface appeared to be key parameters in achieving surface passivation of silicon.