Effect of grain boundaries on the formation of luminescent porous silicon from polycrystalline silicon films

Abstract

Luminescent porous silicon can be obtained by electrochemical etching under illumination from n-type polycrystalline silicon which has been fabricated by solid phase crystallization of in situ doped amorphous films deposited by low pressure chemical vapor deposition. The analyses of the nanostructures by microscopy show that the pore orientations mainly follow the current flow which is channeled by macropores located at grain boundaries. The luminescence results obtained from this porous polycrystalline silicon are comparable to those obtained from porous samples of single-crystals silicon.