Efficiency improvement in InP thin film solar cell using dielectric nanobars

Abstract In this paper, to significantly improve the conversion efficiency in a 1 μ m InP thin film solar cell, array of perpendicular TiO 2 nanobars and backside grating are employed. TiO 2 nanobars are coated with a desired anti-reflector ( AR ) and partially embedded in the InP film to achieve strong light trapping. Optimizing the size of TiO 2 nanobars leads to an enhancement of 41.5% in the photocurrent current density, J ph , and 49.3% in power conversion efficiency, PCE , related to the conventional InP film. For boosting the long wavelength absorption, a back reflector ( BR ) structure including six SiO 2 layers with Si nanopyramid arrays is applied at the backside of the absorption film. Compared to the 1 μ m InP thin film solar cell, the J ph and PCE are improved by 52.7% and about 59%, respectively. Finite-Difference-Time-Domain (FDTD) and Finite-Element-Method (FEM) are used to obtain the results.