P. Menna et al., POROUS SILICON IN SOLAR-CELLS - A REVIEW AND A DESCRIPTION OF ITS APPLICATION AS AN AR COATING, Solar energy materials and solar cells, 37(1), 1995, pp. 13-24
In this paper, we first review the potential applications of porous Si
in solar cell structures. Then we describe the fabrication of this ma
terial by both electrochemical and chemical etching methods, providing
some guidelines for a better comprehension of the influence of each p
rocess parameter. After that, the properties of porous Si in terms of
morphology, structure, photoluminescence, and electroluminescence emis
sions are summarized together with their actual photovoltaic applicati
ons. The results of our study specifically address the creation of an
antireflection (AR) coating for polycrystalline Si based solar cells.
We have demonstrated the feasibility of a very efficient porous Si AR
layer, prepared by a simple, cost effective, chemical etching method.
The formation of a porous Si layer about 0.5 mu m thick on the polycry
stalline wafer results in an effective reflectance coefficient R(eff)
lower than 5% in the wavelength region from 350 to 1150 nm. The drasti
c reduction of the optical losses is controllable by the process param
eters and is almost independent of the starting substrate.