Nickel oxide-based hole-selective contact silicon heterojunction solar cells

Abstract

Nickel Oxide (NiOx) based hole-selective contact silicon heterojunction (SHJ) solar cells are fabricated with SiOx and i-a-Si:H surface passivation layers. The power conversion efficiency (η) of ∼17.3% and open-circuit voltage (Voc) of ∼670 mV is achieved from the cell with i-a-Si:H layer compared to η of ∼15.26% and Voc of ∼580 mV with SiOx layer. The significant improvement in Voc of the cell with i-a-Si:H layer is due to better passivation of the silicon surface dangling bonds than the wet chemically grown SiOx layer. Whereas, slightly better short-circuit (Jsc) of ∼1.5 mA/cm2 from the cell with SiOx layer is observed due to minimization of parasitic absorption in the NiOx layer, which is also confirmed by quantum efficiency analysis. The contact resistivity measurements with p-c-Si/NiOx and n-c-Si/NiOx structures are also carried out to verify the hole selectivity properties of the NiOx film. The simulation results with NiOx hole selective layer show a large window to optimize the ITO layer's electronic properties without compromising the device's performance compared to p-a-Si:H hole-selective SHJ cell.