Porous silicon infiltration with advanced materials for their use in third generation of solar cells

In the present work, porous silicon has been prepared using the anodization process on p-type siliocn wafers. Scanning Electron Microscopy (SEM), Fourier tranform infrared (FTIR) spectrosocpy and Photoluminescence (PL) spectroscopy were applied to investigate the structural, morphological and optoelectronic properties of the samples. By optimizing the current denisty from 12 mA/cm
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to 30 mA/cm
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and then finally, 50 mA/cm
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pore diameter was controlled from (7.8 ± 1.9) nm to (22.6 ± 5.5) nm for the deposited samples. Then, two different techqniques were empoyed for the pore infilteration in order to have the formation of p-n junction. In the first technique, plasma enhance chemical vapor deposition (PECVD) was used to fill the pores with amorphous silicon doped with phosphine and to have the formation of p-n junction. On the other hand, in the other technique pore filling was carried out using the diluted orthophosphoric acid. Finally, after the formation of junction, AZO was deposited by sputtering technique as a transparent contact. And again the characterization techniques were employed to test the final samples. In the PL spectrocopy it was found that the emisison was dimnished after the formation of p-n junction which is a good signal of the formation of junction in this case. Finally, using a simple multimeter an overall comparison was made in the open circuit voltage (Voc) measurement under 0.6 sun of the two different structures and it was found that the samples with p-n junction using orthophosphoric acid presented an overall voltage of around 487 mV, whereas, samples with PECVD shown an open circuit voltage of around 146 mV. In the future, more device testing will be carried out using external efficiency measurements and I-V characteristics for the better understanding of the final device and could provide a gateway for the new generation of solar cells based on silicon technology.