RCWA-based Investigation of Incident Wavelength Effects on Amorphous Silicon Thin-film Solar Cell

In the study, the effect of the incident wavelength of 600 nm on the performance of a thin-film amorphous silicon solar cell was determined. The Rigorous Coupled-wave Analysis (RCWA) method was used to investigate the interaction of electromagnetic waves in transverse electric (TE) and transverse magnetic (TM) polarizations with an amorphous silicon solar cell. At the nanoscale level, nanostructures were integrated to improve the light-harvesting mechanism. Initially, the distributed Bragg reflector (1 DBR to 5 DBR) was optimized for the center wavelength (λc = 600 nm) based on reflectivity and integrated as a backside reflector. The optimized 5 DBR (Si/SiO2), triangular bottom gratings (silver), and rectangular top gratings (indium tin oxide) played a significant role. Light harvesting improved within a 50 nm thick amorphous silicon absorber region, resulting in a conversion efficiency of up to 15.75% and a current density of 23.9 mA/cm2, through the photonic modes under TE polarization. In the future, these design and structural parameters could be applied to miniaturized photovoltaic devices.