Al2O3/Ag/Al2O3 passivating and conducting stacks for crystalline silicon solar cells

• A novel configuration of Al2O3/Ag/Al2O3 was put forward for silicon passivation.
• The excellent conductivity of the stacks was certified by vertical and horizontal measurements.
• A low surface recombination of the passivated silicon wafer was obtained.
• The fixed charge changed from negative to positive with increasing Ag thickness.

The purpose of this work is to investigate the passivating and conducting layers of crystalline silicon solar cells. The Al2O3/Ag/Al2O3 stack was chosen because of the free carrier injection effect of this structure. A resistivity as low as 2.81 × 10− 5 Ω cm was achieved with a 16 nm Ag interlayer. The current-voltage measurements indicate that the current density increases with the increasing thickness of the Ag layers. The passivation properties of the stacks were examined by effective minority carrier lifetime measurements. The annealing process was applied to study the thermal stability of the thin film stacks. The best sample yielded an effective surface recombination velocity of approximately 50 cm/s and a resistivity of approximately 3.0 × 10− 5 Ω cm. Moreover, the fixed charges of the investigated structures varied according to the thickness of the Ag layers. The experimental results demonstrated the promising potential of Al2O3/Ag/Al2O3 stacks as passivating and conducting layers for crystalline silicon solar cells.