Book/Dissertation / PhD Thesis

FZJ-2020-04170

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Zinc Oxide / Nanocrystalline Silicon Contacts for Silicon Heterojunction Solar Cells

Li, H. (Corresponding author)FZJ*

2020
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-508-6

Please use a persistent id in citations: http://hdl.handle.net/2128/26328  urn:nbn:de:0001-2020120114

Abstract: The silicon heterojunction (SHJ) solar cell is one of the most promising technologies and draws intensive attention due to its high conversion efficiency with low temperature coefficient and low energy consumption in production. Reducing the cost of cell fabrication is one of the key challenges to overcome for mass production. Usage of abundant materials and low-cost scalable production processes is a way to reduce cost. This work is focused on the replacement of conventional indium tin oxide (ITO) with aluminum-doped zinc oxide (AZO), which is a more environmentally friendly, abundant, and less costly transparent conductive oxide material. Layers of AZO were prepared with industrially relevant magnetron sputtering process at low temperature to address both scalability and cost reduction for future production lines. Optical and electronic properties of AZO implemented in rear-emitter SHJ solar cells is addressed in this study. To reduce parasitic absorption of the window layer and form proper contact between doped silicon (Si) layer and AZO, doped hydrogenated nanocrystalline Si (n-type or p-type nc-Si:H)layers were used in the SHJ solar cells instead of the conventional doped hydrogenated amorphous Si (n-type or p-type a-Si:H) layers. The optical and electrical properties of doped nc-Si:H layers and AZO films were optimized for the application in SHJ solar cells. Moreover, the influence of AZO sputtering on the passivation quality of Si layer stacks was investigated and the contacts at the interfaces between AZO and p-type Si layers were studied. Furthermore, loss analysis of photovoltaic parameters, such as open circuit voltage (V$_{oc}$), fill factor (FF), series resistance (R$_{s}$), and short circuit current density (J$_{sc}$) of SHJ solar cells with AZO was carried out after the experimental analysis. Various contact combinations between AZO and doped Si layers were tested in SHJ solar cells. It was observed that the solar cells with the combination of AZO and doped amorphous Si layers or n-type nc-Si:H layer operated properly. However, severe s-shaped illuminated current density voltage(J-V) curves were observed in SHJ solar cells when AZO was in contact with p-type nc-Si:H layers. The s-shaped J-V characteristic is a result of a carrier collection barrier at the rear side of the device located at the interface between p-type nc-Si:H and AZO. Increasing the doping inp-type nc-Si:H layer or inserting a seed layer prior to the p-type nc-Si:H layer resulted insuppression of the contact barrier. However, increase of either the doping concentration or the sputtering temperature of AZO films did not contribute to the reduction of contact barrier. [...]

Note: RWTH Aachen, Diss., 2019

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Contributing Institute(s):

1. Photovoltaik (IEK-5)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Appears in the scientific report 2020

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Database coverage:
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