Porous surface silicon layers in silicon solar cells

The porous silicon (PSi) layers have been studied in the aspect of their application in the multicrystalline silicon (mc-Si) solar cells. The macroporous layers were prepared by double-step chemical etching prior to the donor diffusion. They have been investigated using scanning (SEM) and transmission (TEM) electron microscopy to reveal the morphology of PSi layers. The techniques of spectral response and current-voltage characteristics have been used to determine the opto-electrical parameters of the solar cells. The porosity was measured by the mercury porosimetry and nitrogen sorption method. The porous layers reported here have had a sponge-like homogeneous structure over the whole 25 cm 2 surface of each sample and the decreased effective reflectance (R-eff) below 10%. As a final result the me-Si solar cells with PSi layer were obtained with the conversion efficiency ((Eff)) over 13%.