FDTD-Based Optimization of Geometrical Parameters and Material Properties for GaAs-Truncated Nanopyramid Solar Cells

Solar cells (SCs) based on semiconductor nanostructures with the distinctive potential of significant savings in material and effective control over light trapping and scattering processes provide a pathway to low-cost and high-efficiency next-generation SCs. To realize efficient light harvesting and reduced reflection and transmission loss of the nanostructures, the geometrical parameters and material properties must be deliberately optimized. In this article, for SCs based on vertically aligned GaAs-truncated nanopyramids, using the 3-D finite-difference time-domain (FDTD) method, we have examined the optimization study of geometrical and material parameters, including base-width, period, top-surface flatness, carrier mobility and lifetime, doping concentration, and surface recombination, to achieve absorption enhancement and in turn optimum photovoltaicparameters. The optimized structure has exhibited an efficiency of 19.16% despite considering low carrier mobility of 1000 cm ² V ^-1 s ^-1 and lifetime of 3 nanoseconds, with heavily doped core (~4 × 10 ¹⁷ cm ^-3 ) and substrate (~1 × 10 ¹⁹ cm ^-3 ) and surface recombination velocity of 10 ⁵ cm/s at the contacts.