p–n Junction formed in structures with macro-porous silicon

Boron doped glasses, obtained from organic solution under low temperature and deposited by spin-on technique, were used to form a highly doped pq–n junction into structures with macro-porous silicon PS.layer of 0.4–6 mm thickness. The junction was found to lie about 2.5 mm deeper than the bottom of the pores, and almost independent on their thickness. Enhanced boron diffusion was explained by a presence of local electric fields, caused by tensions present at the border between PS layer and crystalline substrate. Reflectivity values of less than 10% were obtained over 450–1050 nm wavelength range for samples with PS layer, confirming the light-trapping effect in electrochemically etched structures. q2000 Elsevier Science B.V. All rights reserved.