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

Abstract

Commonly used first layer antireflection (AR) coatings for InP solar cells, such as ZnS, Sb/sub 2/O/sub 3/, SiO/sub 2/ 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/sub 3/, o-H/sub 3/PO/sub 4/ and H/sub 2/O/sub 2/. The chemical oxide grown on p/sup +/-InP emitters, using the PNP etchant, passivates the surface and can be used as a first layer AR coating.<>