Characteristics of silicon nanowire solar cells with a crescent nanohole.

In recent years, newly emerging photovoltaic (PV) devices based on silicon nanowire solar cells (SiNW-SCs) have attracted considerable research attention. This is due to their efficient light-trapping capability and large carrier transportation and collection with compact size. However, there is a strong desire to find effective strategies to provide high and wideband optical absorption. In this paper, a modified circular nanowire (NW) with a nanocrescent hole is newly introduced and analyzed for solar cell applications. The crescent hole can strongly improve the light absorption through the NW due to the excitation of numbers of modes that can be coupled with the incident light. The material index, volume, and position of the nanohole are studied to significantly increase the optical absorption efficiency and hence the power conversion efficiency (PCE). The absorption performance can be further preserved by using a silicon substrate due to the coupling between the supported modes by the NW, and that of the substrate. The optical and electrical characteristics of the suggested design are investigated using finite difference time domain and finite element methods via Lumerical software packages. The reported asymmetric design offers higher optical and electrical efficiencies compared to the conventional NW counterpart. The proposed NW offers a short circuit current density (J) of 33.85 (34.35) mA/cm and power conversion efficiency (PCE) of 16.78 (17.05) % with an enhancement of 16.3 (16.8) % and 17.3 (18.4) % for transverse magnetic (TM) and transverse electric (TE) polarizations, respectively, compared to the conventional cylindrical counterpart.