The enhanced light trapping nature of NiOx thin films deposited by magnetron sputtering onto silicon solar cells at room temperature

Nickel oxide (NiOx) thin films were successfully deposited onto silicon solar cells (SSCs) using dc magnetron sputtering. The effect of the optical absorption–emission process of light with thickness of NiOx thin films (NiOx-TFs) and its influence on the electrical process of SSCs modified were investigated. Atomic force microscopy (AFM) showed that the particle size of NiOx-TFs increased with an increasing thickness, x-ray diffraction (XRD) indicated that the samples only presented the NiO phase, x-ray photoelectron spectroscopy (XPS) studies showed that the films clearly exhibited the presence of an oxidation state of Ni2+.The reflectance and transmission were measured with thicknesses of 1, 2 and 3 nm and the absorbance edges were obtained which overlapped the pseudo edge of the glass substrate at 315 nm. While the thickness of 20 nm NiOx-TFs showed edge at 330 nm, with an optical band gap of 3.75 eV. Furthermore, electrical properties depend on the films thickness, exhibited PCE around 1.06, 2.27 and 0.77% (fixed holder) and 1.54, 1.38 and −0.65% (moveable holder) for nominal thicknesses of 1, 2 and 3 nm respectively.