Characteristics of highly efficient star-shaped nanowires solar cell

The optical characteristics of a star-shaped silicon nanowires (Si NWs) solar cell (SC) are numerically studied using three-dimensional (3-D) finite-difference time-domain (FDTD). The particle swarm optimization technique is used to optimize the geometrical parameters of the NW to maximize its light absorption. The optimized star-shaped Si NWs offer high ultimate efficiency (eta) of 43.7% while its complementary design achieves eta of 40.1%. This is due to the star surface textures that allow multiple light scattering between the NWs. This will increase the optical path length through the NW and improve its light absorption. The electrical properties of the proposed design are also calculated using the finite-element method. In this investigation, the doping level of the star-shaped Si NWs with p - i - n axial and radial configurations is simulated to quantify the optoelectronic performance of the reported design. The p - i - n axial doped design offers power conversion efficiency (PCE) of 21%; however, the p - i - n radial doping gives PCE of 21.3%. Therefore, the star-shaped design violates PCE of 17.3% and 15.9% of the conventional Si NWs with axial and radial doping, respectively. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)