Light coupling info mechanically, textured encapsulated silicon solar
cells is studied by three-dimensional comprehensive ray tracing with o
ur newly developed programme SUNRAYS. We analyse periodic textures wit
h symmetric and non-symmetric pyramids and grooves. The facet angles o
f the textures are varied systematically. The study considers the appa
rent daily motion of the sun and diffuse illumination SUNRAYS accounts
for the dependence of reflection and transmission on the wavelength,
the angle of incidence and the polarization of light. As a result of b
asic interest, we show that the maximum average path length theoretica
lly possible under isotropic illumination is actually achieved by nume
rous trapping schemes. As a result of practical interest, we demonstra
te the outstanding performance of the simple prism groove texture, whi
ch yields a large current density while preserving a small surface whe
n compared to all other textures investigated.