In my research I found a gleam of hope. It is possible to use EBSD technique to determine the crystallographic orientation of individual grains in the polycrystalline silicon wafer despite the fact that surface is not smooth. This means that I will be able to examine what is the actual effect of acid etching on the grains orientation and whether this method is really isotropic.

In addition, I found a nice link to the e-learning platform in photovoltaics:
http://pveducation.org/pvcdrom

Enjoy :)