Influence of intermediate layers on the surface condition of laser crystallized silicon thin films and solar cell performance

Journal Article · Thu Jan 28 04:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4940953· OSTI ID:22494959

Höger, Ingmar; Gawlik, Annett; Brückner, Uwe; Andrä, Gudrun ^[1]; Himmerlich, Marcel; Krischok, Stefan ^[2]

---

1. Leibniz-Institut für Photonische Technologien, PF 100239, 07702 Jena (Germany)
2. Institut für Mikro-und Nanotechnologien, Technische Universität Ilmenau, PF 100565, 98684 Ilmenau (Germany)

The intermediate layer (IL) between glass substrate and silicon plays a significant role in the optimization of multicrystalline liquid phase crystallized silicon thin film solar cells on glass. This study deals with the influence of the IL on the surface condition and the required chemical surface treatment of the crystallized silicon (mc-Si), which is of particular interest for a-Si:H heterojunction thin film solar cells. Two types of IL were investigated: sputtered silicon nitride (SiN) and a layer stack consisting of silicon nitride and silicon oxide (SiN/SiO). X-ray photoelectron spectroscopy measurements revealed the formation of silicon oxynitride (SiO{sub x}N{sub y}) or silicon oxide (SiO{sub 2}) layers at the surface of the mc-Si after liquid phase crystallization on SiN or SiN/SiO, respectively. We propose that SiO{sub x}N{sub y} formation is governed by dissolving nitrogen from the SiN layer in the silicon melt, which segregates at the crystallization front during crystallization. This process is successfully hindered, when additional SiO layers are introduced into the IL. In order to achieve solar cell open circuit voltages above 500 mV, a removal of the formed SiO{sub x}N{sub y} top layer is required using sophisticated cleaning of the crystallized silicon prior to a-Si:H deposition. However, solar cells crystallized on SiN/SiO yield high open circuit voltage even when a simple wet chemical surface treatment is applied. The implementation of SiN/SiO intermediate layers facilitates the production of mesa type solar cells with open circuit voltages above 600 mV and a power conversion efficiency of 10%.

• OSTI ID: 22494959
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 119; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CRYSTALLIZATION
ELECTRIC POTENTIAL
GLASS
HETEROJUNCTIONS
LASERS
LAYERS
LIQUIDS
NITROGEN
SILICON
SILICON NITRIDES
SILICON OXIDES
SOLAR CELLS
SURFACE TREATMENTS
SURFACES
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY