Study and analysis the Cu nanoparticle assisted texturization forming low reflective silicon surface for solar cell application

Abstract

Monocrystalline silicon solar cells with photo-absorbing morphology can amplify light-trapping properties within the absorber layer and help to fabricate cost-effective solar cells. In this paper, the effect of different parameters namely temperature and time of Cu-assisted chemical etching was thoroughly investigated for the optimization of the light absorption properties. P-type monocrystalline wafers were selectively treated with Cu(NO3)2.3H2O:HF:H2O2:DI water solution at 50 °C for five different time duration. The entire process was repeated at five different temperatures for 20min as well to study the relation between etching temperature and surface reflectance. Sonication bathing was used for the removal of the deposited Cu atoms from the surface with the variation of time and the effect was examined using energy dispersive spectroscopy (EDS). Field emission scanning electron microscopy (FESEM) and UV/VIS spectroscopy were conducted to study the surface morphology and light absorbance respectively. Inverted shapes almost similar to inverted pyramids or porous surface were found randomly on the surface of the wafer. The effect of temperature was found more significant compared to the effect of time variation. An optimum light reflectance was found at 50 °C for 20 min of texturization. Atomic force microscopy (AFM) of the textured sample revealed the average depth of pyramidal shape was about 1.58 μm. EDS results showed a proportional relation between time and Cu removal process, and a complete Cu atoms free textured surface after 25 min of sonication bathing. Therefore, a suitable Cu-assisted texturization technique was found, which could enable lowering the photo-reflectance below 1% without any antireflection coating.