Broadband light trapping in a-Si:H based plasmonic solar cells using Au core-Al₂O₃ shell composite nanospheres using FDTD method

In this work, two different geometries of Au core-Al2O3 shell composite nanospheres (CNS) in ITO/a-Si:H based solar cell structure have been considered. A finite-difference time domain (FDTD) analysis of optical and electrical properties for both geometries has been conducted using open-source software MEEP. When embedded in the active layer of the cell, Au core-Al2O3 shell CNS exhibit relatively high scattering efficiency over a broad spectrum. Maximum normalized scattering efficiency for ‘CNS on top’ geometry has been found 18.16 while that for ‘embedded CNS’ geometry it boosts up to 19.62. The localized surface plasmon resonance wavelength achieves a value of 738.9nm for ‘CNS on top’ and 835.8nm for ‘embedded CNS’ configurations. Furthermore, reflectance of the incident radiation reduces significantly with the shell thickness leading to effective light trapping. This study provides an important design to enhance the efficiency of silicon based plasmonic solar cells.