Refined optoelectronic properties of silicon nanowires for improving photovoltaic properties of crystalline solar cells: a simulation study

Abstract

Tremendous works have been devoted on reducing the materials costs and searching a low-cost antireflection (AR) layer in silicon (Si) solar cells. This work reports on the surface architectural of Si wafer (p-type) by growing the nanowires (NWs)-like structures through cost-effective wet-controlled etching method. The nanostructures over Si wafer were optimized in terms of sizes, lengths and densities by changing the etching conditions and thoroughly examined their growth and optoelectrical properties. The well-defined grown NWs textured on Si wafer exhibited the low average reflectance of ~ 2.25% in the full visible-NIR spectrum from 400 to 1000 nm which was well matched to the simulated average reflectance of 2.23%. A model was designed using PC1D simulation to evaluate the photovoltaic (PV) parameters of NWs textured Si wafer-based solar cells without AR layer. In this simulation, the length of SiNWs and reflectance were selected as input parameters to instigate the power conversion and quantum efficiencies of solar cells. The highest conversion efficiency of ~ 16.2% is observed when the average length of SiNWs and reflectance were ~ 2.52 μm and ~ 2.25%, respectively. Experimentally, the fabricated SiNWs-based solar cell with etching time of 20 min attained the highest conversion efficiency of 15.9% and the value was very close to simulated results. PV parameters of SiNWs-based solar cells without AR layer were comparable to commercial c-Si solar cells with SiNx AR layer. Thus, the controlled wet etching is an easy, facile method for fabrication of nanowires on Si wafer with low reflectance. The enhancement in optical and electrical properties would be expected to a great prospect in developing low-cost c-Si solar cells without AR layer.