Nickel Oxide Hole‐Selective Heterocontact for Silicon Solar Cells: Role of SiOx Interlayer on Device Performance. Issue 11 (16th August 2019)

• Record Type: Journal Article
• Authors: Nayak, Mrutyunjay; Mandal, Sourav; Pandey, Ashutosh; Mudgal, Sapna; Singh, Sonpal; Komarala, Vamsi K.
• Is Part Of: Solar RRL. Volume 3:Issue 11(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-16
• Subjects: carrier-selective contacts -- heterojunction silicon solar cells -- lithium fluoride -- nickel oxide -- SiOx passivation; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900261
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Carrier‐selective contact‐based silicon heterojunction solar cells are fabricated using nickel oxide (NiO x ) as a hole‐selective layer by thermal evaporation. The highest power conversion efficiency of ≈15.20% with a chemically grown SiO x interlayer is achieved from a Ag/ITO/NiO x /n‐Si/LiF x /Al cell structure in comparison with ≈12.43% without SiO x . The cells without and with the SiO x layer are analyzed by considering crucial parameters for conversion efficiency, such as minority carriers' diffusion lengths, lifetimes, recombination resistance, and density of interface defect states at the NiO x /n‐Si junction, by studying the dark/light current density–voltage, quantum efficiency, impedance, and parallel conductance characteristics. Device analysis provides evidence for the cell's open‐circuit voltage and short‐circuit current enhancement with the SiO x interlayer. This is due to an improvement in minority carrier lifetimes from ≈8.6 to ≈48.27 μs (photo‐conductance decay analysis), which is also estimated from ≈7.45 to ≈49.20 μs by impedance spectra analysis, increased minority carrier diffusion length from ≈171 to ≈952 μm, and decreased rear surface recombination velocity from ≈1106 to ≈170 cm s −1 (quantum efficiency analysis). These investigations reveal that engineering the n‐Si/LiF x interface by the SiO x interlayer is more important than the NiO x /n‐Si interface because of a thin unintentionally grown SiO x layer during NiO x evaporation simultaneously mediating silicon surface passivation. Abstract : Nickel oxide (NiO x )‐based carrier‐selective contact Ag/ITO/NiO x /n‐Si/LiF x /Al solar cells are fabricated. The highest reported power conversion efficiency of ≈15.20% is achieved with a chemically grown SiO x passivation layer on silicon in comparison with devices without SiO x (efficiency ≈12.43%). Devices are analyzed systematically for performance enhancement with SiO x and evidence for contact‐resistivity, minority‐carriers' lifetimes/diffusion‐lengths, recombination‐resistance, and density of interface‐defect‐states at the NiO x /n‐Si interface is provided.