Nanoparticles-decorated silicon absorber: Absorption depth profile characteristics within absorbing layer

Abstract

Here in this work, we carried out a simple and hand-on experiment to fabricate silver (Ag) nanoparticles on substrate (either Zinc oxide (ZnO) or p-Silicon (Si)) that could be used as base layer for thin film solar design in substrate and superstrate configurations. As-fabricated Ag nanoparticles were found to be ca. 100 nm on average and of wide range of interparticle gap distribution. Based on experimental observations, a typical model, “Ag nanoparticles array on c-Si” has been simulated in finite deference time domain (FDTD) analysis to understand the inherent optical characteristic such as absorption depth profile within Si layer. Model parameters such as solar incident wavelengths (450 nm, 650 nm and 1100 nm) and interparticle gaps (0, 1 and 3 nm) were varied and corresponding characteristics were analyzed. At 450 nm incident wavelength, absorption was localized at the interstitials as usual and propagated distribution within Si layer was observed for interacting nanoparticles array. In such case nearly half of the volume of Si absorbing layer got higher absorption distribution. At 650 nm incident wavelength, such absorption distribution within Si layer was found wide spread compared to those observed at 450 nm and 1100 nm incident wavelengths. Considering the fabrication process and predicted absorption profile in FDTD, a possible route to substrate and superstrate configuration of Si-based PIN solar cell was proposed. Such correlated investigations would facilitate in depth understanding as well as the development of emerging process needed to advance highly efficient design in photovoltaic technologies particularly plasmonic solar cells.