Epitaxial Interdigitated Back Contact (IBC) solar cell test platform for novel light trapping schemes

Abstract

An Interdigitated Back Contact (IBC) solar cell is being developed for evaluation of emerging light trapping schemes of silicon nanowire arrays on pyramidal textured surfaces. The front surface of the baseline IBC cell design was optimized with a thin film coating considering both antireflection and passivation to reduce surface recombination. Addition of a front surface field (FSF) was shown to improve the surface passivation of the cell. PC2D simulations of the baseline device predict an efficiency of 17.4%. Silicon nanowire arrays and hybrid structures of silicon nanowires on pyramids were successfully fabricated. Hemispherical reflectance measurements show that a weighted average reflectance of just 1.89% was achieved. With adequate surface passivation, these highly-effective antireflective structures could result in a power conversion efficiency increase compared to traditional light trapping methods when incorporated into the IBC cell.