24.4% industrial tunnel oxide passivated contact solar cells with ozone-gas oxidation Nano SiOx and tube PECVD prepared in-situ doped polysilicon

Abstract

Ozone-gas oxidation (OGO) technology, capable of integrating into tube plasma-enhanced chemical vapor deposition (PECVD) technology, is developed to prepare the Nano SiO x layer for tunnel oxide passivated contact (TOPCon) solar cells in this work. The effects of gas flow, oxidation temperature, and annealing temperature on passivation quality are investigated. The X-ray photoelectron spectroscopy (XPS) indicates that OGO SiO x possesses a Si 4+ proportion of about 20%, higher than the nitric acid oxidized (NAOS) SiO x and plasma-assisted N 2 O oxidation (PANO) SiO x . The implied open-circuit voltage ( iV oc ) of the hydrogenated lifetime sample is promoted to more than 740 mV with the highest value of 748 mV, corresponding to a lowest single-sided saturation current density ( J 0,s ) of 3.1 fA/cm 2 . The contact resistivity extracted from the Cox-Strack method is < 9 mΩ cm 2 as the annealing temperature is more than 840 °C. Finally, we prepared the large-sized TOPCon solar cells with an average efficiency of 24.37% and a maximum efficiency of 24.41%, respectively. The above work shows that the tube PECVD technology integrated with ozone gas oxidation has the potential for the mass-production TOPCon industry. • Ozone-gas oxidation (OGO) technology is integrated into tube PECVD technology. • OGO SiO x and P-doped a-Si:H can be prepared by the same graphite-boat carrier. • OGO SiO x shows a high proportion of Si 4+ without ion bombardment. • The highest iV oc of 748 mV corresponding to the lowest J 0,s of 3.1 fA/cm 2 . • Average efficiency of 158.75 mm TOPCon cells reaches ∼24.4%.