The effects of geometry on drift-limited solar cells

We present analytical simulations for the performance of nanocoaxial and -hemispherical drift-limited solar cells, to determine optimal geometrical configuration and to interpret results of experimental nanocoaxial solar cell arrays. The material system considered in these simulations is hydrogenated amorphous silicon (a-Si:H), with solar cells designed in an n–i–p stack. Simulations conducted for the performance of planar devices are compared against simulations performed using SCAPS-1D and are found to be in close agreement. Simulation of the nanocoaxial array shows that while geometrical changes in the energy band diagram impact charge carrier collection, performance is most significantly impacted by light absorption properties associated with incident light interacting with the array of non-planar nanostructures. We compare our simulations to results of fabricated nanocoaxial a-Si:H solar cells.