Numerical Simulation on the Photovoltaic Behavior of an Amorphous-Silicon Nanowire-Array Solar Cell

In this letter, we propose an amorphous-silicon (a-Si) solar cell with a nanowire-array structure. The proposed structure has photon absorption and carrier transport that are perpendicular to each other, which could overcome the efficiency limit of an a-Si solar cell. This nanowire structure has an n-type a-Si nanowire array in which the i-layer and the p-layer a-Si are sequentially grown along the surface of the nanowire. Under illumination, light is absorbed along the axial direction of the nanowire, and carrier transport is along the radial direction. Numerical simulations show that the photocurrent of the a-Si solar cell with a 4000-nm-long nanowire is nearly 40% more than that of a planar a-Si solar cell. A conversion efficiency of 11.6% was obtained, which is around 32% enhancement.