Investigation on TiO2 spin-coated thin films effect on the optoelectronic properties of stain-etched porous silicon for solar cell applications

This article aims to improve the opto-electronic properties of porous silicon (PS) to integrate it as an anti-reflecting coating in solar cell applications. The enhancement of its properties is achieved through the passivation of its surface by titanium dioxide (TiO₂). Samples of porous silicon were elaborated using stain etching technique, then treated with the metal oxide using spin-coating technique. The film thickness was varied to study the thickness effect on the properties of the TiO₂/PS structure. Morphological study has shown that most pores were covered with TiO₂ structures, resulting in an overall change in the surface morphology. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis has confirmed the TiO₂ deposition on PS surface. The passivation of PS with TiO₂ had more interesting results, especially in the case of PS passivated with three layers of TiO₂, which suggests a good coverage of the surface of PS, results confirmed by optical study and minority carrier lifetime measurement. Moreover, a simulation was also carried out using PC1D. The optoelectronic results of the synthesized TiO₂/PS samples were applied on a built-in model of a commercialized silicon-based solar cell. The efficiency increased from 11% for an untreated silicon solar to 15.8% for the cell modeled with 3 layers of TiO₂ deposited on PS.