Influence of molybdenum oxide thickness, electronic structure, and work function on the performance of hole selective silicon heterojunction solar cells

摘要

Ultra-thin MoO_x is capable of exhibiting high work function (<; 6 eV), large band gaps (<; 3 eV) are benefiting for surface passivation and hole selectivity layer in silicon solar cells instead of the doped layers due to high parasitic absorption. Importantly, MoO_x electronic structure by oxygen dilution during the evaporation have influence to the MoO_x work function and hence reduce hole injection. XPS study confirmed the electronic structure and chemical composition of the evaporated and annealed (Ar and O₂ atmosphere) MoO_x sample. TEM showed a clear interface contact between the ITO/MoO_x/a-SiH(i) layers and no diffusion between the layers after annealed at 140 °C. Fabricated 10 nm thick MoO_x-Si solar cells archived an efficiency of 20.04%, FF of 73.79 % and J_sc of 38.40 mA/cm². A sever degradation in FF and J_sc was noticed by increasing the MoO_x thickness due to diffusion of layers and high parasitic absorption of MoO_x.