Improved passivation performance of Al2O3 interlayer/MoOX thin films continuously grown via atomic layer deposition

• Published in: Thin solid films Vol. 766; p. 139667
• Main Authors: Jeong, Minji, Park, Jihye, Cho, Young Joon, Chang, Hyo Sik
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Aluminum oxide; Atomic layer deposition; Molybdenum oxide; Oxidation state; Surface passivation; Molybdenum oxide; Atomic layer deposition; Oxidation state; Surface passivation; Aluminum oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2022.139667

•Low temperature ALD-Al2O3 interlayer and ALD-MoOx film grown at 170°C.•Improved passivation characteristics of Al2O3/MoOX films continuously grown via ALD.•Al2O3 changes suboxide states and increase to Si4+ to form network that mimicked SiO2.•1 nm ALD-Al2O3 interlayer reduced defect and increased the work function of ALD-MoOx. Atomic-layer-deposited MoOx was investigated as a hole-selective layer in Si heterojunction solar cells. MoOx grown on Si through atomic layer deposition (ALD) produce numerous sub-oxidation states at the MoOx/Si interface. The passivation of interface states remains an important problem for hole-selective contact Si solar cells. We improved the passivation of interface defects in the ALD-MoOx/Si structure by introducing ultrathin ALD-Al2O3 at 443 K for continuous processing with ALD-MoOx. Consequently, the carrier lifetime and implied open-circuit voltage increased from 22 μs to 215 μs and 568 mV to 637 mV, respectively. The introduction of ultrathin ALD-Al2O3 significantly reduced the number of oxidation states that acted as defects. The best passivation was observed up to 907 μs and 676 mV after post-deposition annealing at 623 K. The ALD-MoOX film prepared by introducing ultrathin Al2O3 is a promising hole-selective contact layer.