Impact of incident light angle on the conversion efficiency of nano-structured GaAs solar cells

Abstract

This paper presents the impact of incident angle of sun lights on the conversion efficiency of nano-structured GaAs solar cells. The incident light angle plays an important role on the conversion efficiency of GaAs solar cells or panels. Over the day, the incident angle of the sunlight falling on the solar cell or panel varies from morning to afternoon and influences the light capturing of the cells or panels, hence affecting the conversion efficiency. The nano-grating structure with effective incident angle can trap more sunlight into the solar cells. In simulation, different nano-grating structures are considered, such as elliptical, triangular, trapezoidal and rectangular shaped with various grating heights from 100-nm to 400-nm. Finite difference time domain (FDTD) simulation tool is used to simulate the light reflection, transmission and absorption in GaAs solar cells. From the simulation results, it has confirmed that the variation of incident light angle affects the light reflection losses, transmission, and absorption for all types of nano-grating shapes. Hence, this simulation results predicted that the light reflection loss is always least for the aspect ratio 0 ∼ 0.5 at 0° incident angle, whereas the incident angle has less impact on the nano-grating height above 300 nm.