Efficiency enhancement in SiGe thin film solar cell by a CNT grating structure

In this paper, a new structure of SiGe thin film solar cell using a carbon nanotubes (CNT) grating layer is proposed. CNT grating layer is used which reduces the reflection loss from the surface and maximizing optical absorption in the active layer of the cell. In order to reduce the carrier recombination in the back contact, a GaAs back-surface field (BSF) layer was used. The simulation results show that the efficiency of the proposed structure is 29.32%. Furthermore, we were able to increase the efficiency to 31.3% by optimizing the structural parameters including the depth and number of grating periods.