Al ₂ O ₃ /MoO x Hole-Selective Passivating Contact for Silicon Heterojunction Solar Cell

Carrier selective contact (CSC) layers have been extensively studied to realize high passivation effect in solar cells. Excellent passivation properties of Al 2 O 3 and a-Si:H(i) as passivating interlayers between the hole-selective contact (HSC) MoO x and p-type c-Si wafer surface are reported herein. MoO x single layer exhibits a high work function value (≥5.0 eV), which can cause sufficient band bending in the band structure for HSC. An Al 2 O 3 /MoO x contact exhibits a significantly higher transmittance and surface passivation compared with that of an a-Si:H(i)/MoOx contact. The passivation results for Al 2 O 3 /MoO x contact are a carrier lifetime (τ eff ) of 830 μ s and implied open circuit voltage (iV OC ) of 726 mV, whereas for conventional a-Si:H(i)/MoO x contact, the corresponding values are 770 μ s and 716 mV. Delicate thickness optimization was performed using experimental and simulation results for Al 2 O 3 /MoO x and a-Si:H(i)/MoO x stacks to achieve high performance in p-type c-Si solar cells.