Investigation of Atomic Layer Deposition Al2O3Passivation for Screen-Printed Large-Area Solar Cells

Abstract

Thermal and plasma-assisted atomic layer deposition (ALD) ${\mathrm{A}}{{\mathrm{l}}_2}{{\mathrm{O}}_3}$ films for surface passivation of Si solar cells are investigated. ALD ${\mathrm{A}}{{\mathrm{l}}_2}{{\mathrm{O}}_3}$ films were deposited on both Czochralski (Cz) and float-zone wafers with textured and planar surface, and then, surface recombination velocity (SRV) was measured. An extremely low SRV of 3 cm/s after annealing and 13 cm/s after contact firing was achieved from plasma-assisted ALD ${\mathrm{A}}{{\mathrm{l}}_2}{{\mathrm{O}}_3}$ on a 2-Ω⋅cm Cz wafer. In addition, screen-printed large-area (239-cm2) textured solar cells were fabricated using plasma-assisted ALD ${\mathrm{A}}{{\mathrm{l}}_2}{{\mathrm{O}}_3}$ films and compared with ${\mathrm{Si}}{{\mathrm{O}}_{\rm{2}}}$ -passivated solar cells. Superior conversion efficiency of 20.0% (n-type) and 18.6% (p-type) was achieved from ALD ${\mathrm{A}}{{\mathrm{l}}_2}{{\mathrm{O}}_3}$ passivation, while ${\mathrm{Si}}{{\mathrm{O}}_{\rm{2}}}$ -passivated solar cells provide 19.8% (n-type) and 17.7% (p-type).