Effective first layer antireflective coating on InP solar cells grown by chemical oxidation

Commonly used first layer antireflection (AR) coatings for InP solar cells, such as ZnS, Sb₂O₃, SiO₂ and SiO, deposited either by electron-beam or by resistive evaporation, destroy the stoichiometry of the emitter surface. Consequently, the surface recombination velocity (SRV) at the emitter surface is significantly increased, leading to a reduction in the values of solar cell performance parameters. This can be prevented by growing, after contacting, a thin native oxide layer on the emitter surface. Best results are obtained using a phosphorus-rich chemical oxide grown by chemical oxidation using a newly developed etchant (PNP) based on HNO ₃, o-H₃PO₄ and H₂O₂ . The chemical oxide grown on p⁺-InP emitters, using the PNP etchant, passivates the surface and can be used as a first layer AR coating