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

Abstract

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.