Copper nanoclusters in thin film solar cells: Bridging FDTD analysis and fabrication

Copper (Cu) has emerged as a game-changing material for thin-film solar cells due to its unique properties. To address the inherent inefficiency of photon absorption in conventional silicon solar cells, this study investigates the influence of Cu nanoclusters embedded within a silicon substrate using Finite-Difference Time-Domain (FDTD) simulations. A model titled "Cu Nanocluster Array on Silicon" was developed, and absorption depth profiles were extracted at various incident wavelengths across the solar spectrum for different interparticle gaps in the Cu nanocluster array. The results revealed that the absorption distribution within the silicon substrate was strongly dependent on both the incident wavelength and the spatial arrangement of the Cu nanoclusters. To experimentally validate the simulation results, a straightforward fabrication strategy was implemented using a sputtering technique to create Cu nanoclusters. High-resolution Field Emission Scanning Electron Microscopy (FESEM) images showed that the average diameter of the fabricated Cu clusters was approximately 100 nm. Based on over 50 measurements, the size distribution was determined to have a mean of 101.75 nm with a full width at half maximum (FWHM) of 12.5 nm. Additionally, Energy-Dispersive X-ray Spectroscopy (EDS) confirmed the elemental composition of the Cu nanoclusters. These correlated experimental and simulation investigations provide valuable insights into the optical behavior of plasmonic nanostructures and support the development of advanced, high-efficiency photovoltaic technologies, particularly in the field of plasmonic solar cells.