Influence of nanostructure geometry on light trapping in solar cells

Abstract

The aim of this research was to detect the influence of the silicon nanowires geometry and silver nanoparticles on the wafer surface on light trapping for application in solar cells with radial p–n junction. Si-NWs arrays were fabricated on p-type (100) silicon wafers with specific resistance of 10 Ω × cm. We used MacEtch method to form Si nanowires. In our study to deposit the additional silver nanoparticles on the surface of the nanowires, the flushing time was reduced to 10 min. The structural and optical properties of silicon nanowires were studied. The absorption, transmittance and reflectance spectra for periodic nanostructures with different parameters were calculated by FDTD (Finite-Difference Time-Domain) method. The FDTD method is a powerful numerical algorithm for direct solution of Maxwell’s equations. The realization of this method is discrete both in space and in time. The presented structures are described on a discrete mesh consisting of Yee cells and the Maxwell equations. They are solved discretely over time on this grid. As a result, through the method of the catalytic etching, we obtained nanowires of 0.5–2 μm in length and diameter in range of 50–100 nm. The diameter of silver nanoparticles was in the range of 20–50 nm. The reflection coefficient of light in wide spectral range was less than 1%. Reflection spectra peaked at the wavelength of 850 nm that points out on the influence of Ag nanoparticles.